You wouldn't think that was a tough question - most doctors and therapists assessing risk in teenagers ask this simple question every day - but an accurate answer seems hard to get. A new study from the Kinsey Institute at Indiana University found no consensus among people 18- to 96 year-year-old when they were asked that question.
Thirty percent of the people did not consider oral sex, having sex. Twenty percent did not consider anal sex, having sex, and the winner - only 89% considered vaginal sex having sex if there was no ejaculation. (Can I just say, hay carumba!)
This lack of consensus suggests that just asking the question, "have you had sex," is pretty much a waste of time, unless you are very specific about the type of behavior you are asking about. In addition, if people do not consider these activities sexual, they are likely not worrying about the sexual risks associated with them. Be clear, be considered!