Dulcinea said:
Second: coercing a fifteen-year-old (and it is coercing) to have sex with you (rape them) might be less physically damaging,
A 16 year old who has sex with a 15 year old, is technically a rapist and a child abuser (16 being the age of consent here). Thing is, 15 year olds usually know what they are doing. People don't suddenly, on their 16th birthday, wake up and discover a new ability to judge whether or not they should have sex.
My point being that it probably isn't coercing. In fact, from what I've seen I'd suggest a lot of the time 14 or 15 year old girls coerce older guys to sleep with them. In some countries, Spain being the one I can think of, the legal age is as low as 13. I'd say 15 year olds know how to handle themselves, barring any psychological or developmental issues.
OT: Personally, I think rape is rape. Ignoring the issue of child abuse, which is different to standard rape, so not really relevant, I think any rape is a rape. Yes, some may be more violent or whatever, but any rapist should get the same time, because they are awful, horrible people.
(Also, it isn't just women who get raped. Men can be raped by other men and by women.)
Edit - Actually, maybe rape isn't just rape. There are different circumstances, I retract that statement.