Sexually transmitted diseases (STDs) are infections transmitted through sexual contact. STDs generally infect the genital area (penis, scrotum, vulva and vaginal opening), but can also be transmitted to the anus or mouth. They can spread to other parts of the body if left untreated.

STDs can be transmitted in two ways. The first is through bodily fluids including semen, pre-cum, vaginal fluids and blood. These fluids are often passed between partners during oral, anal or vaginal sex. This means that if you have any type of sex with someone who has an STD, you can get the infection. (Activities you do on your own, like masturbation, do not transmit STDs.)

Some STDs, such as genital warts or herpes, can also be spread through the skin-to-skin contact that happens with other sexual behavior. This means touching an infected person’s genitals and then touching yourself or rubbing genitals with someone who has one of these STDs. Herpes can be spread through kissing or to the genitals through oral sex.

The only 100 percent effective way to avoid infection is to abstain from oral, anal and vaginal sex.

Got a question about STDs? Call the American Social Health Association’s national hotline at 1-919-361-8488. , The hotline is open 8 a.m.–8 p.m. EST.