Rubber pants or rubber panties were the predecessor to plastic pants

Plastic pants

Plastic pants are devices worn over a diaper for the purpose of containing liquid or solid waste that may otherwise leak through the fabric. Today, "plastic pants" are usually made out of polyvinyl chloride or polyurethane though, in some instances, the traditional latex rubber is still used...

 and served the purpose of a diaper

Diaper

A nappy or a diaper is a kind of pant that allows one to defecate or urinate on oneself discreetly. When diapers become soiled, they require changing; this process is often performed by a second person such as a parent or caregiver...

 cover, replacing the woolen garment. However, "rubber pants" is still a generic term for any pull-on or snap-on incontinence protective garment.

Lacking a fly front, the traditional variant is a true panty. As an infants' garment they had fallen out of favor in the 1950s, but were still the primary adult incontinence protective garment and in that role were called "rubber bloomers".

Rubber pants for infants wear over cloth diapers fell into two categories. Some were made of natural rubber and had rubber gathers at the waist and legs. The rubber pant itself was sized generously so the stretchy characteristic of rubber was not utilized and some air circulation took place within the oversized pants. Some were made of latex rubber that utilized the stretchy characteristic and fit very snugly over the diaper, leaving no air space.

Perhaps the best known of these stretchy latex pants were introduced by Playtex

Playtex

Playtex and PlayTex are a brand and trademark. It used to be associated with bras and women's undergarments. Currently there are two separate companies with the Playtex name....

. Playtex baby pants stretched over the diaper much like rubber gloves are stretched over a hand. Undersized leg holes and waist opening allowed the stretchy latex rubber to seal against the skin to contain diaper wetness and therefore protect what ever the baby was placed upon. Ventilation was supposedly provided by two slots (holes) in the front of the pants up near the waist but they did little more than allow leakage onto the bed when baby slept on its stomach.

Stretchy, molded latex pants for adults are mostly limited to the fetish

Fetish

Fetish may refer to:* Fetishism, the attribution of religious or mystical qualities to inanimate objects* Sexual fetishism, sexual attraction to objects, body parts, or situations not conventionally viewed as being sexual in nature....

 market, being supplied primarily as wear for "rubberists", who enjoy wearing rubber and latex. Molded latex pants for incontinent wear are not common but can be ordered over the Internet.

They have now been almost entirely replaced by plastic or waterproof textile panties as an infants' garment, when such is used over a diaper at all. Today they exist mainly in the adult incontinence market.

Modern Rubber Pants

Parents opting to cloth diaper their children now have several options in a diaper cover. They can use a wool cover, a polyurethane PUL

Polyurethane

A polyurethane is any polymer composed of a chain of organic units joined by carbamate links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer with another monomer in the presence of a catalyst.Polyurethanes are...

or a breathable polar fleece cover. These modern rubber pants are plentiful and can be found all over the internet and at several large chain stores.