Risky sexual behavior is the most complicated form of antisocial risky teenage behavior, both in its manifestations and in terms of availability for study and interventions. Sexual behavior and romantic relationships of teenagers are viewed, on the one hand, as important developmental stages, encouraging one's positive psychosocial adaptation, on the other hand, as an element of one's problem behavior profile with lots of unfavorable outcomes, e.g. sexually transmitted diseases, unwanted pregnancies etc, as well as a number of associated risks (substance use, offences etc). The article presents major research focuses dealing with the problem of risky teenage behavior, including the role of genetics, factors of social environment, and also the key results concerning the relationship between adolescents' risky sexual behavior and characteristics of their families, other teens of the same age around them, specifics of the area of their residence and of their local community, as well as adolescents' trade of sexual services.