Every year more than 15 million cases of STDs are reported in the U.S. If you engage in sexual activity (outside of marriage), you are very likely to contract at least one STD. In addition, you (or your partner) may have an STD but not know it yet, because some have delayed symptoms. Damage to your body can still occur even if there are no symptoms. Teens are especially susceptible to STDs due to their anatomy and that they have a lower level of antibodies (which fight infection) than adults.

This chart shows on the left the number of sexual partners and on the right the number of people exposed to. This is assuming that everyone has the same sexual partners as you. This chart demonstrates how a promiscuous lifestyle is extremely susceptible to sexually transmitted diseases.

"When you have sex with someone, you are having sex with everyone they have had sex with for the last ten years,
and everyone they and their partners have had sex with for the last ten years."
C. Everett Koop, M.D., Former U.S. Surgeon General