During your teens you go through puberty and become sexually mature. If you're a girl, you develop breasts and begin to get your period. If you're a boy, your penis and testicles become larger. If you have sex, you could get pregnant or get someone pregnant. Whether you choose to have sex or not, it is a good idea to know about safe sex and how sex affects your health. Besides pregnancy, having sex puts you at risk of getting a sexually transmitted disease (STD), such as chlamydia, HPV, or HIV/AIDS
The only way to be completely safe is not to have sex. If you do choose to have any kind of sexual contact, latex condoms are the best protection against STDs. Condoms are also a form of birth control to help prevent pregnancy.