No... that's not usually the case in these situations. A 15-year-old boy is dealing with a ton of hormones and sometimes is unable to resist the temptation to take advantage of a younger, vulnerable, trusting girl, usually in the family, a close friend or neighbor. It happens much more than you, apparently, know. The tragic thing is that sometimes even a relatively minor contact can make the teenager panic and that's when the violence occurs. Frankly, I'm surprised anyone has to explain this to you...