Condoms were first made of animal intestines, most notably sheep intestines. These condoms are still used today, however, the material used to make most male condoms is latex. Female condoms are made of thin polyurethane.
Condoms are not 100% effective, however they greatly reduce the risks of pregnancy and contracting sexually transmitted diseases or infections. Other types of birth control, like the birth control pill or patch, do not protect against STDs and STIs.