A condom can be used only once.
Although some condoms have spermicide added (the spermicide is usually nonoxynol-9 in the United States) to kill sperm, spermicide has not been scientifically shown to provide additional contraceptive protection over a condom alone.
Because they act as a mechanical barrier, condoms prevent direct vaginal contact with semen, infectious genital secretions, and genital sores and discharges.
Most condoms are made from latex rubber, while a small percentage are made from lamb intestines (sometimes called "lambskin" condoms). Condoms made from polyurethane have been marketed in the United States since 1994.
Except for abstinence, latex condoms are the most effective method for reducing the risk of infection from the viruses that cause AIDS, other HIV-related illnesses, and other sexually transmitted diseases (STDs).
Some condoms are prelubricated. These lubricants do not provide more birth control or STD protection. Non-oil-based lubricants, such as water or K-Y jelly, can be used with latex or lambskin condoms, but oil-based lubricants, such as petroleum jelly (Vaseline), lotions, or massage or baby oil, should not be used because they can weaken the material.