20 overall, around teenagers contract an sti sexually transmitted infection) each year.

overall, around twenty million teenagers contract an STI (sexually transmitted infection) each year. (The half of them are from U.S.)

A sexually transmitted infection (STI) is an infection that is transmitted between partners during different forms of sexual intercourse. This infection can lead to an infectious disease, formerly called venereal disease (the name comes from Venus, goddess of love)All sexual practices that involve mutual genital or oro-genital contact with another person, or genital fluids, are considered to carry a risk of transmitting an STI. Each STI has a different risk and severity.