Diapers have been worn throughout human history. They are made of cloth or disposable materials. Cloth diapers are composed of layers of fabric such as cotton, hemp, bamboo or microfiber and can be washed and reused multiple times. Disposable diapers contain absorbent chemicals and are thrown away after use. The decision to use cloth or disposable diapers is a controversial one, owing to issues ranging from convenience, health, cost, and their effect on the environment. Plastic pants can be worn over diapers to avoid leaks, but with modern cloth diapers, this is no longer necessary.
Diapers are primarily worn by children who are not yet potty trained or experience bedwetting. However, they can also be used by adults with incontinence or in certain circumstances where access to a toilet is unavailable. These can include the elderly, those with a physical or mentaldisability, and people working in extreme conditions such as astronauts. It is not uncommon for people to wear diapers under dry suits. Diapers are usually worn out of necessity rather than choice, although there are exceptions; people such as infantilists and diaper fetishists wear diapers recreationally for comfort, emotional fulfillment, or sexual gratification. Terms such as "incontinence pads" can be used to refer to adult diapers.