Condoms are a thin rubber tube which fits over the man's erect penis before intercourse.
When the man ejaculates, he does so into the condom which prevents the sperm from entering the vagina. Most condoms are made of latex and when coated with spermicide are considered an effective means of protection from pregnancy and the spread of STDs. There are other condoms available which are made of animal intestine but these are less effective for disease prevention. Furthermore, condoms provide excellent protection from the spread of sexually transmitted diseases, although the exact rates of success are unknown. The latex condom is the recommended form of STD and pregnancy prevention.