Human variability
Encyclopedia
Human variability, or human variation, is the range of possible values for any measurable characteristic, physical or mental, of human beings. Differences can be trivial or important, transient or permanent, voluntary or involuntary, congenital or acquired, genetic or environmental. This article discusses variabilities that characterize a person for all or much of his or her lifetime, and are perceived as not purely learned or readily changed (such as religion, language, customs, or tastes). Each person being different is so essential a part of human experience that it is difficult to even imagine a human existence in which other people are identical. Furthermore, the social value put on these differences by the society in which one lives affects every aspect of a person's life.
While nearly all of the variables listed above are at least partially determined or affected by genetic factors, few of them are controlled by simple Mendelian inheritance
. Most are polygenic or are determined by a complex combination of genes and early environment. Essentially, genes provide proclivities and potentialities continuously involving feedback mechanisms with the environment throughout life, but especially during prenatal and early childhood
.
Many genetic differences (polymorphisms
) have little effect on health or reproductive success, but serve to statistically distinguish one population from another. Researchers in the field of population genetics
have been using these to elucidate ancient migrations and relationships between population groups.
Another purely genetic set of individual differences are the blood type
s and immune types we all carry. While some may carry mild advantages or disadvantages in terms of risks of particular diseases, the primary life-or-death significance comes when we attempt to transfer blood or organs from one person to another. Our immune system
is designed to recognize these human differences with great sensitivity and enforce our individuality.
Possession of above average amounts of some abilities is valued by most societies: ability to learn; musical aptitude; strength, endurance, agility; resilience.
Each individual's distinctive differences, even the negatively valued ones, are usually considered an essential part of self-identity.
Membership or status in a social group may depend on having specific values for certain attributes. It is not unusual for people to deliberately try to amplify or exaggerate differences, or to conceal or minimize them, for a variety of reasons. Examples of practices designed to minimize differences include hair straightening
or skin bleaching, plastic surgery
, orthodontia
, and growth hormone treatment
for extreme shortness. Conversely, male-female differences are enhanced and exaggerated in most societies.
These differences may vary or be distributed in various ways. Some, like height for a given sex, vary in close to a "normal" or Gaussian distribution. Some characteristics (e.g., skin color) vary continuously in a population, but the continuum may be socially divided into a small number of distinct categories. Some characteristics vary bimodally (for example, handedness
), with fewer people in intermediate categories.
Different human societies may assign different values to various differences. The obvious examples are race and sex, while handedness has a much weaker value difference, but nearly all human differences will have social value dimension. In some societies, such as the United States
, circumcision
is practiced on a majority of males, as well as sex reassignment
of intersex
infants, with substantial emphasis on cultural norms.
Much social controversy surrounds the assigning or distinguishing of some categories, with variation between groups in a society or between societies as to the degree to which a difference is part of a person's "essential" nature
or is partly a socially constructed attribution. For example, in the United States and Europe there has been a centuries-long debate over whether sexual orientation is an essential part of one's nature (the "essentialist" position), or a result of mutually reinforcing social perceptions and behavioral choices (the "constructivist" perspective). Other cultures may not even understand the controversy.
Controversy also surrounds the boundaries of "wellness
", "wholeness," or "normality
." In some cultures, physical imperfections can exclude one from religious service. In western culture there has been large-scale renegotiation of the social significance of variations which reduce the ability of a person to do one or more functions. Laws have been passed to alleviate the reduction of social opportunity available to those with disabilities
. The concept of "differently abled" has been pushed by those persuading society to see limited incapacities as a human difference of less negative value.
When an inherited difference of body structure or function is severe enough, it is termed a genetic disease, but even this classification has fuzzy edges. There are many instances in which the degree of negative value of a human difference depends completely on the social or physical environment. For example, in a society with a large proportion of deaf people (as Martha's Vineyard
in the 19th century), it was possible to deny that deafness is a disability. Another example of social renegotiation of the value assigned to a difference is reflected in the controversy over management of ambiguous genitalia, especially whether abnormal genital structure has enough negative consequences to warrant surgical correction.
Furthermore, many genetic traits may be advantageous in certain circumstances and disadvantageous in others. Being a heterozygote or carrier
of the sickle-cell disease
gene confers some protection against malaria, apparently enough to maintain the gene in populations of malarial areas. In a homozygous dose it is a significant disability.
The extreme exercise of social valuation of human difference is in the definition of "human." What difference is great enough to assign an individual "nonhuman" status, in the sense of withholding our identification, charity, and social participation? This can change enormously between cultures and over time. For example, nineteenth century European and American ideas of race and eugenics
culminated in the attempts of the Nazi
-led German society of the 1930s to deny not just reproduction, but life itself to a variety of people with "differences" attributed in part to biologic characteristics. Western society's revulsion to this contributed to a considerable readjustment of valuation of differences.
Contemporary controversy continues over "what kind of human" is a fetus or child with a significant disability. On one end are people who would argue that Down's syndrome is not a disability but a mere "difference," and on the other those who consider such a calamity as to assume that such a child is better off "not born
". In India and China, being female is widely considered such a negatively valued human difference that similar decisions are made by the hundreds of thousands.
Acknowledgement and study of human differences does have a wide range of uses, such as tailoring the size and shape of manufactured items. See Ergonomics
.
Sources of human variability
- biological inheritance, shaped by
- mutationMutationIn molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
s, allelic differencesAlleleAn allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation... - genetic driftGenetic driftGenetic drift or allelic drift is the change in the frequency of a gene variant in a population due to random sampling.The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces...
- natural selectionNatural selectionNatural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
- prenatal environment and fetal "programming"
- artificial or cultural selection
- nutritionNutritionNutrition is the provision, to cells and organisms, of the materials necessary to support life. Many common health problems can be prevented or alleviated with a healthy diet....
and malnutritionMalnutritionMalnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions.... - quality of lifeQuality of lifeThe term quality of life is used to evaluate the general well-being of individuals and societies. The term is used in a wide range of contexts, including the fields of international development, healthcare, and politics. Quality of life should not be confused with the concept of standard of...
and health careHealth careHealth care is the diagnosis, treatment, and prevention of disease, illness, injury, and other physical and mental impairments in humans. Health care is delivered by practitioners in medicine, chiropractic, dentistry, nursing, pharmacy, allied health, and other care providers... - pollutionPollutionPollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
and toxinToxinA toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
exposure and other stressors - educationEducationEducation in its broadest, general sense is the means through which the aims and habits of a group of people lives on from one generation to the next. Generally, it occurs through any experience that has a formative effect on the way one thinks, feels, or acts...
- cultural environmentCultureCulture is a term that has many different inter-related meanings. For example, in 1952, Alfred Kroeber and Clyde Kluckhohn compiled a list of 164 definitions of "culture" in Culture: A Critical Review of Concepts and Definitions...
- social environmentSocial environmentThe social environment of an individual, also called social context or milieu, is the culture that s/he was educated or lives in, and the people and institutions with whom the person interacts....
- family environment and upbringingFamilyIn human context, a family is a group of people affiliated by consanguinity, affinity, or co-residence. In most societies it is the principal institution for the socialization of children...
(especially before age 5)- child abuse and neglectChild abuseChild abuse is the physical, sexual, emotional mistreatment, or neglect of a child. In the United States, the Centers for Disease Control and Prevention and the Department of Children And Families define child maltreatment as any act or series of acts of commission or omission by a parent or...
- child abuse and neglect
- accidental, industrialIndustrial injuryAn occupational injury is bodily damage resulting from working.In the United States in 2007, 5,488 workers died from job injuries, 92% of which were men, and 49,000 died from work-related injuries. NIOSH estimates that 4 million workers in the U.S...
or intentional injury, mutilationMutilationMutilation or maiming is an act of physical injury that degrades the appearance or function of any living body, usually without causing death.- Usage :...
, or change of the body
- mutation
While nearly all of the variables listed above are at least partially determined or affected by genetic factors, few of them are controlled by simple Mendelian inheritance
Mendelian inheritance
Mendelian inheritance is a scientific description of how hereditary characteristics are passed from parent organisms to their offspring; it underlies much of genetics...
. Most are polygenic or are determined by a complex combination of genes and early environment. Essentially, genes provide proclivities and potentialities continuously involving feedback mechanisms with the environment throughout life, but especially during prenatal and early childhood
Child
Biologically, a child is generally a human between the stages of birth and puberty. Some vernacular definitions of a child include the fetus, as being an unborn child. The legal definition of "child" generally refers to a minor, otherwise known as a person younger than the age of majority...
.
Many genetic differences (polymorphisms
Polymorphism (biology)
Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph...
) have little effect on health or reproductive success, but serve to statistically distinguish one population from another. Researchers in the field of population genetics
Population genetics
Population genetics is the study of allele frequency distribution and change under the influence of the four main evolutionary processes: natural selection, genetic drift, mutation and gene flow. It also takes into account the factors of recombination, population subdivision and population...
have been using these to elucidate ancient migrations and relationships between population groups.
Another purely genetic set of individual differences are the blood type
Blood type
A blood type is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells . These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system...
s and immune types we all carry. While some may carry mild advantages or disadvantages in terms of risks of particular diseases, the primary life-or-death significance comes when we attempt to transfer blood or organs from one person to another. Our immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
is designed to recognize these human differences with great sensitivity and enforce our individuality.
Social significance and valuation of human variability
Human beings rarely give all possible values for a given parameter of the same value, though not all people agree on the values or relative rankings. Examples of differences which may be given different values in different societies include darker/lighter skin color or thinness/fatness. Local valuation may affect social standing, reproductive opportunities, or even survival.Possession of above average amounts of some abilities is valued by most societies: ability to learn; musical aptitude; strength, endurance, agility; resilience.
Each individual's distinctive differences, even the negatively valued ones, are usually considered an essential part of self-identity.
Membership or status in a social group may depend on having specific values for certain attributes. It is not unusual for people to deliberately try to amplify or exaggerate differences, or to conceal or minimize them, for a variety of reasons. Examples of practices designed to minimize differences include hair straightening
Hair straightening
Hair straightening is a hair styling technique which involves the flattening and straightening of hair in order to give it a smooth, streamlined, and 'sleek' appearance. It may be accomplished by using hair irons and hot combs, chemical relaxers, Japanese hair straightening, or Brazilian hair...
or skin bleaching, plastic surgery
Plastic surgery
Plastic surgery is a medical specialty concerned with the correction or restoration of form and function. Though cosmetic or aesthetic surgery is the best-known kind of plastic surgery, most plastic surgery is not cosmetic: plastic surgery includes many types of reconstructive surgery, hand...
, orthodontia
Orthodontics
Orthodontics, orthodontia, or orthodonture is the first specialty of dentistry that is concerned with the study and treatment of malocclusions , which may be a result of tooth irregularity, disproportionate jaw relationships, or both...
, and growth hormone treatment
Growth hormone treatment
Growth hormone treatment refers to the use of growth hormone in medical treatment. Growth hormone is a peptide hormone secreted by the pituitary gland that stimulates growth and cell reproduction. In the past, growth hormone was extracted from human pituitary glands. GH is now produced by...
for extreme shortness. Conversely, male-female differences are enhanced and exaggerated in most societies.
These differences may vary or be distributed in various ways. Some, like height for a given sex, vary in close to a "normal" or Gaussian distribution. Some characteristics (e.g., skin color) vary continuously in a population, but the continuum may be socially divided into a small number of distinct categories. Some characteristics vary bimodally (for example, handedness
Handedness
Handedness is a human attribute defined by unequal distribution of fine motor skills between the left and right hands. An individual who is more dexterous with the right hand is called right-handed and one who is more skilled with the left is said to be left-handed...
), with fewer people in intermediate categories.
Different human societies may assign different values to various differences. The obvious examples are race and sex, while handedness has a much weaker value difference, but nearly all human differences will have social value dimension. In some societies, such as the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, circumcision
Circumcision
Male circumcision is the surgical removal of some or all of the foreskin from the penis. The word "circumcision" comes from Latin and ....
is practiced on a majority of males, as well as sex reassignment
Sex reassignment
Sex reassignment may refer to:* Sex reassignment, changing the sex assignment of an infant or child by parents and doctors, usually because of fuller understanding of an intersex condition....
of intersex
Intersex
Intersex, in humans and other animals, is the presence of intermediate or atypical combinations of physical features that usually distinguish female from male...
infants, with substantial emphasis on cultural norms.
Much social controversy surrounds the assigning or distinguishing of some categories, with variation between groups in a society or between societies as to the degree to which a difference is part of a person's "essential" nature
Nature (innate)
Nature is innate behavior , character or essence, especially of a human. This is a way of using the word nature which goes back to its earliest forms in Greek...
or is partly a socially constructed attribution. For example, in the United States and Europe there has been a centuries-long debate over whether sexual orientation is an essential part of one's nature (the "essentialist" position), or a result of mutually reinforcing social perceptions and behavioral choices (the "constructivist" perspective). Other cultures may not even understand the controversy.
Controversy also surrounds the boundaries of "wellness
Wellness (alternative medicine)
Wellness is generally used to mean a healthy balance of the mind, body and spirit that results in an overall feeling of well-being. It has been used in the context of alternative medicine since Halbert L. Dunn, M.D., began using the phrase high level wellness in the 1950s...
", "wholeness," or "normality
Normality (behavior)
In behavior, normal refers to a lack of significant deviation from the average. The phrase "not normal" is often applied in a negative sense Abnormality varies greatly in how pleasant or unpleasant this is for other people.The Oxford English Dictionary defines "normal" as "conforming to a standard"...
." In some cultures, physical imperfections can exclude one from religious service. In western culture there has been large-scale renegotiation of the social significance of variations which reduce the ability of a person to do one or more functions. Laws have been passed to alleviate the reduction of social opportunity available to those with disabilities
Disability
A disability may be physical, cognitive, mental, sensory, emotional, developmental or some combination of these.Many people would rather be referred to as a person with a disability instead of handicapped...
. The concept of "differently abled" has been pushed by those persuading society to see limited incapacities as a human difference of less negative value.
When an inherited difference of body structure or function is severe enough, it is termed a genetic disease, but even this classification has fuzzy edges. There are many instances in which the degree of negative value of a human difference depends completely on the social or physical environment. For example, in a society with a large proportion of deaf people (as Martha's Vineyard
Martha's Vineyard
Martha's Vineyard is an island located south of Cape Cod in Massachusetts, known for being an affluent summer colony....
in the 19th century), it was possible to deny that deafness is a disability. Another example of social renegotiation of the value assigned to a difference is reflected in the controversy over management of ambiguous genitalia, especially whether abnormal genital structure has enough negative consequences to warrant surgical correction.
Furthermore, many genetic traits may be advantageous in certain circumstances and disadvantageous in others. Being a heterozygote or carrier
Genetic carrier
A genetic carrier , is a person or other organism that has inherited a genetic trait or mutation, but who does not display that trait or show symptoms of the disease. They are, however, able to pass the gene onto their offspring, who may then express the gene...
of the sickle-cell disease
Sickle-cell disease
Sickle-cell disease , or sickle-cell anaemia or drepanocytosis, is an autosomal recessive genetic blood disorder with overdominance, characterized by red blood cells that assume an abnormal, rigid, sickle shape. Sickling decreases the cells' flexibility and results in a risk of various...
gene confers some protection against malaria, apparently enough to maintain the gene in populations of malarial areas. In a homozygous dose it is a significant disability.
The extreme exercise of social valuation of human difference is in the definition of "human." What difference is great enough to assign an individual "nonhuman" status, in the sense of withholding our identification, charity, and social participation? This can change enormously between cultures and over time. For example, nineteenth century European and American ideas of race and eugenics
Eugenics
Eugenics is the "applied science or the bio-social movement which advocates the use of practices aimed at improving the genetic composition of a population", usually referring to human populations. The origins of the concept of eugenics began with certain interpretations of Mendelian inheritance,...
culminated in the attempts of the Nazi
Nazism
Nazism, the common short form name of National Socialism was the ideology and practice of the Nazi Party and of Nazi Germany...
-led German society of the 1930s to deny not just reproduction, but life itself to a variety of people with "differences" attributed in part to biologic characteristics. Western society's revulsion to this contributed to a considerable readjustment of valuation of differences.
Contemporary controversy continues over "what kind of human" is a fetus or child with a significant disability. On one end are people who would argue that Down's syndrome is not a disability but a mere "difference," and on the other those who consider such a calamity as to assume that such a child is better off "not born
Abortion
Abortion is defined as the termination of pregnancy by the removal or expulsion from the uterus of a fetus or embryo prior to viability. An abortion can occur spontaneously, in which case it is usually called a miscarriage, or it can be purposely induced...
". In India and China, being female is widely considered such a negatively valued human difference that similar decisions are made by the hundreds of thousands.
Acknowledgement and study of human differences does have a wide range of uses, such as tailoring the size and shape of manufactured items. See Ergonomics
Ergonomics
Ergonomics is the study of designing equipment and devices that fit the human body, its movements, and its cognitive abilities.The International Ergonomics Association defines ergonomics as follows:...
.
Common human variations
- Sexual orientationSexual orientationSexual orientation describes a pattern of emotional, romantic, or sexual attractions to the opposite sex, the same sex, both, or neither, and the genders that accompany them. By the convention of organized researchers, these attractions are subsumed under heterosexuality, homosexuality,...
(asexualAsexualityAsexuality , in its broadest sense, is the lack of sexual attraction and, in some cases, the lack of interest in sex. Sometimes, it is considered a lack of a sexual orientation...
, bisexualBisexualityBisexuality is sexual behavior or an orientation involving physical or romantic attraction to both males and females, especially with regard to men and women. It is one of the three main classifications of sexual orientation, along with a heterosexual and a homosexual orientation, all a part of the...
, heterosexualHeterosexualityHeterosexuality is romantic or sexual attraction or behavior between members of the opposite sex or gender. As a sexual orientation, heterosexuality refers to "an enduring pattern of or disposition to experience sexual, affectional, physical or romantic attractions to persons of the opposite sex";...
, homosexualHomosexualityHomosexuality is romantic or sexual attraction or behavior between members of the same sex or gender. As a sexual orientation, homosexuality refers to "an enduring pattern of or disposition to experience sexual, affectional, or romantic attractions" primarily or exclusively to people of the same...
, pansexualPansexualityPansexuality refers to the potential for sexual attractions, sexual desire, romantic love, or emotional attraction, towards people of all gender identities and biological sexes...
, polysexualPolysexualityPolysexuality is the attraction to more than one gender or sex. It should not be confused with polyamory, the ability to be romantically involved with more than one person at once.-Gender definition:...
) - Human genetic variationHuman genetic variationHuman genetic variation refers to genetic differences both within and among populations. There may be multiple variants of any given gene in the human population , leading to polymorphism. Many genes are not polymorphic, meaning that only a single allele is present in the population: that allele is...
- SexSexIn biology, sex is a process of combining and mixing genetic traits, often resulting in the specialization of organisms into a male or female variety . Sexual reproduction involves combining specialized cells to form offspring that inherit traits from both parents...
(MaleMaleMale refers to the biological sex of an organism, or part of an organism, which produces small mobile gametes, called spermatozoa. Each spermatozoon can fuse with a larger female gamete or ovum, in the process of fertilization...
, femaleFemaleFemale is the sex of an organism, or a part of an organism, which produces non-mobile ova .- Defining characteristics :The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male...
, see also intersexIntersexIntersex, in humans and other animals, is the presence of intermediate or atypical combinations of physical features that usually distinguish female from male...
) - Race
- Skin or eye colorEye colorEye color is a polygenic phenotypic character and is determined by two distinct factors: the pigmentation of the eye's iris and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris....
ing, complexionComplexionComplexion refers to the natural color, texture, and appearance of the skin, especially that of the face.-History:The word "complexion" is derived from the Late Latin complexi, which initially referred in general terms to a combination of things, and later in physiological terms, to the balance of... - Hair colorHair colorHair color is the pigmentation of hair follicles due to two types of melanin: eumelanin and pheomelanin. Generally, if more melanin is present, the color of the hair is darker; if less melanin is present, the hair is lighter...
, baldnessBaldnessBaldness implies partial or complete lack of hair and can be understood as part of the wider topic of "hair thinning". The degree and pattern of baldness can vary greatly, but its most common cause is male and female pattern baldness, also known as androgenic alopecia, alopecia androgenetica or...
, hirsutismHirsutismHirsutism or frazonism is the excessive hairiness on women in those parts of the body where terminal hair does not normally occur or is minimal - for example, a beard or chest hair. It refers to a male pattern of body hair and it is therefore primarily of cosmetic and psychological concern...
, body hair - Supernumerary body partSupernumerary body partSupernumerary body parts are most commonly a congenital disorder involving the growth of an additional part of the body and a deviation from the body plan. Body parts may be easily visible or hidden away, such as internal organs....
(such as PolydactylismPolydactylyPolydactyly or polydactylism , also known as hyperdactyly, is a congenital physical anomaly in humans, dogs, and cats having supernumerary fingers or toes....
, Supernumerary nippleSupernumerary nippleA supernumerary nipple is an additional nipple occurring in mammals, including humans...
s, Hyperdontia) or missing body parts (such as Hypogenesis) - Cleft lip and Cleft palate
- Sex
- Body shape and sizeAnthropometryAnthropometry refers to the measurement of the human individual...
- HeightHuman heightHuman height is the distance from the bottom of the feet to the top of the head in a human body standing erect.When populations share genetic background and environmental factors, average height is frequently characteristic within the group...
- ShortnessShort statureShort stature refers to a height of a human being which is below expected. Shortness is a vague term without a precise definition and with significant relativity to context...
, dwarfismDwarfismDwarfism is short stature resulting from a medical condition. It is sometimes defined as an adult height of less than 4 feet 10 inches , although this definition is problematic because short stature in itself is not a disorder....
, Little peopleLittle peopleLittle people have been part of the folklore of many cultures in human history, including Ireland, Greece, the Philippines, the Hawaiian Islands, Flores Island, Indonesia, and Native Americans.-Native American folklore:... - Tallness, gigantismGigantismGigantism, also known as giantism , is a condition characterized by excessive growth and height significantly above average...
- Shortness
- Body type/Somatotype, thinness, obesityObesityObesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
- Height
- Motor skillMotor skillA motor skill is a learned sequence of movements that combine to produce a smooth, efficient action in order to master a particular task. The development of motor skill occurs in the motor cortex, the region of the cerebral cortex that controls voluntary muscle groups.- Development of motor skills...
s, handednessHandednessHandedness is a human attribute defined by unequal distribution of fine motor skills between the left and right hands. An individual who is more dexterous with the right hand is called right-handed and one who is more skilled with the left is said to be left-handed...
, dexterity - Physical disabilities
- AmputationAmputationAmputation is the removal of a body extremity by trauma, prolonged constriction, or surgery. As a surgical measure, it is used to control pain or a disease process in the affected limb, such as malignancy or gangrene. In some cases, it is carried out on individuals as a preventative surgery for...
, loss of limbs or limb function - BlindnessBlindnessBlindness is the condition of lacking visual perception due to physiological or neurological factors.Various scales have been developed to describe the extent of vision loss and define blindness...
, color blindnessColor blindnessColor blindness or color vision deficiency is the inability or decreased ability to see color, or perceive color differences, under lighting conditions when color vision is not normally impaired... - Deafness, tone deafness
- MutenessMutenessMuteness or mutism is an inability to speak caused by a speech disorder. The term originates from the Latin word mutus, meaning "silent".-Causes:...
- DiseaseDiseaseA disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
s and defects of other organ systems
- Amputation
- Reproductive attributes
- virginityVirginityVirginity refers to the state of a person who has never engaged in sexual intercourse. There are cultural and religious traditions which place special value and significance on this state, especially in the case of unmarried females, associated with notions of personal purity, honor and worth...
- fertilityFertilityFertility is the natural capability of producing offsprings. As a measure, "fertility rate" is the number of children born per couple, person or population. Fertility differs from fecundity, which is defined as the potential for reproduction...
- parentParentA parent is a caretaker of the offspring in their own species. In humans, a parent is of a child . Children can have one or more parents, but they must have two biological parents. Biological parents consist of the male who sired the child and the female who gave birth to the child...
hood
- virginity
- Human developmentHuman development (biology)Human development is the process of growing to maturity. In biological terms, this entails growth from a one-celled zygote to an adult human being.- Biological development:...
- ageAgeingAgeing or aging is the accumulation of changes in a person over time. Ageing in humans refers to a multidimensional process of physical, psychological, and social change. Some dimensions of ageing grow and expand over time, while others decline...
- childhoodChildhoodChildhood is the age span ranging from birth to adolescence. In developmental psychology, childhood is divided up into the developmental stages of toddlerhood , early childhood , middle childhood , and adolescence .- Age ranges of childhood :The term childhood is non-specific and can imply a...
- pubertyPubertyPuberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...
/adolescenceAdolescenceAdolescence is a transitional stage of physical and mental human development generally occurring between puberty and legal adulthood , but largely characterized as beginning and ending with the teenage stage... - menopauseMenopauseMenopause is a term used to describe the permanent cessation of the primary functions of the human ovaries: the ripening and release of ova and the release of hormones that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining...
- age
- Other aspects of human physical appearanceHuman physical appearanceHuman physical appearance refers to the outward phenotype or look of human beings. There are infinite variations in human phenotypes, though society reduces the variability to distinct categories...
- attractivenessPhysical attractivenessPhysical attractiveness refers to a person's physical traits which are perceived to be aesthetically pleasing or beautiful. The term often implies sexual attractiveness or desirability, but can also be distinct from the two; for example, humans may regard the young as attractive for various...
(highly subjective, variable, and impermanent) - acquired variability in physical appearance
- body modificationBody modificationBody modification is the deliberate altering of the human body for any non-medical reason, such as aesthetics, sexual enhancement, a rite of passage, religious reasons, to display group membership or affiliation, to create body art, shock value, or self expression...
- body modification
- attractiveness
- PsychologicalPsychologyPsychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...
and personality traits- Intelligence, spatial aptitude
- TemperamentTemperamentIn psychology, temperament refers to those aspects of an individual's personality, such as introversion or extroversion, that are often regarded as innate rather than learned...
, introversion, extroversion, impulsiveness, risk-taking - Developmental disabilityDevelopmental disabilityDevelopmental disability is a term used in the United States and Canada to describe lifelong disabilities attributable to mental or physical impairments, manifested prior to age 18. It is not synonymous with "developmental delay" which is often a consequence of a temporary illness or trauma during...
, cognitive disability, social disability - Emotional stability, mental illnessMental illnessA mental disorder or mental illness is a psychological or behavioral pattern generally associated with subjective distress or disability that occurs in an individual, and which is not a part of normal development or culture. Such a disorder may consist of a combination of affective, behavioural,...
- Musical ability
- Creative abilityCreativityCreativity refers to the phenomenon whereby a person creates something new that has some kind of value. What counts as "new" may be in reference to the individual creator, or to the society or domain within which the novelty occurs...
See also
- AnthropometryAnthropometryAnthropometry refers to the measurement of the human individual...
- AuxologyAuxologyAuxology, sometimes called Auxanology , is a meta-term covering the study of all aspects of human physical growth...
- ErgonomicsErgonomicsErgonomics is the study of designing equipment and devices that fit the human body, its movements, and its cognitive abilities.The International Ergonomics Association defines ergonomics as follows:...
- Genetic disease
- ImmunogeneticsImmunogeneticsImmunogenetics is the branch of medical research that explores the relationship between the immune system and genetics.Autoimmune diseases, such as type 1 diabetes, are complex genetic traits which result from defects in the immune system. Identification of genes defining the immune defects may...
- Population geneticsPopulation geneticsPopulation genetics is the study of allele frequency distribution and change under the influence of the four main evolutionary processes: natural selection, genetic drift, mutation and gene flow. It also takes into account the factors of recombination, population subdivision and population...
- ImprintingImprintingImprinting may refer to:* Genomic imprinting , a mechanism of regulating gene expression* Imprinting , in psychology and ethology* Molecular imprinting, in polymer chemistry...