A condom is a contraceptive device which prevents pregnancy by covering the penis and preventing semen from penetrating the barrier. Condoms are usually made out of latex rubber, but are also made out of lamb intestines. In addition to preventing pregnancy, condoms are also very effective at preventing the transmission of STDs.
Condoms are about 99% effective, but in reality, they only fail when improperly treated. Some of the most common cause of condom failure are:
- Use of petroleum jelly with latex condoms (latex is soluble in petroleum);
- Unrolling the condom the wrong way;
- Using a condom without proper lubrication;
- Re-using a condom.