The first ejaculatory experience of boys is termed semenarche.Spermarche refers to the beginning of development of sperm in boys' testicles at puberty. It contrasts with menarche

Menarche

Menarche is the first menstrual cycle, or first menstrual bleeding, in female human beings. From both social and medical perspectives it is often considered the central event of female puberty, as it signals the possibility of fertility....

 in girls. Depending on their upbringing, cultural differences, and prior sexual knowledge, boys may have different reactions to spermarche, ranging from fear to excitement. Spermarche is one of the first events in the life of a male leading to sexual maturity

Sexual maturity

Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...

. It occurs at the time when the secondary sexual characteristics are just beginning to develop. The age when spermarche occurs is not easy to determine. However, researchers have tried to determine the age in various populations by taking urine

Urine

Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...

 samples of boys and determining the presence of spermatozoa. This process of determining the sperm content in urine is referred to as spermaturia. From various sources it appears that spermarche occurs between the ages of 11–15 years.