High-risk sexual behavior is sex that puts you at risk for sexually transmitted infections (STIs), unplanned pregnancy, and being in a sexual relationship before you're mature enough to know what makes a healthy relationship. Teens and young adults are at higher risk than adults.
Examples of high-risk sexual behavior include:
Unprotected intercourse without male or female condom use, except in a long-term single-partner (monogamous) relationship.
Unprotected mouth-to-genital contact, except in a long-term single-partner relationship.
Early sexual activity, especially before age 18.
Having more than one sex partner.
Having a high-risk partner. (This is a partner who has more than one sex partner or other risk factors.)
Having anal sex or a partner who does, except in a long-term, single-partner relationship.
Having sex with a partner who injects or has ever injected drugs.