The condom covers the penis and stops sperm from entering the vagina.
Condoms are available with or without spermicide and lubricants.
Foam and Vaginal Inserts are placed into the vagina before intercourse and stop or kill sperm. How the Condom and Foam, Vaginal Inserts Work Condoms prevent sperm from entering the vagina so fertilization cannot occur. Some condoms have spermicide which also kills the sperm. Foam and vaginal inserts have a chemical in them that stops the movement of most sperm. These methods kill most sperm and are intended to block any remaining sperm from swimming into the uterus.