Male Condom: A sleeve usually made of latex that fits over the erect penis and blocks sperm from entering the cervix during intercourse. Male condoms are 85 to 98 percent effective, available without a prescription and are usually available widely.

Female Condom: A thin, loose-fitting and flexible plastic sleeve worn inside the vagina. A soft ring at the closed end of the sleeve covers the cervix during intercourse and holds the condom inside the vagina. Female condoms are 79 to 95 percent effective and are available without a prescription. They are not as widely available as male condoms and can be more expensive.

Spermicide (Nonoxynol-9): Foams, jellies, creams, films and suppositories that can be applied inside the vagina. Spermicides are 71 to 95 percent effective and are best used in combination with another method of birth control, such as male or female condoms, diaphragms or cervical caps.