(d) At the time of the commission of the act, the victim is less than fifteen years of age and the actor is at
least four years older than the victim and is not the spouse of the victim;
If you're 17 years old, then 13 year olds are fair game.
According to the letter of the law, that's not true. If the victim is 13, the 17 year old would be committing sexual assault. Hence the "at least four years older" statement. Now, if the victim is 13 and the other person is 16, then it's fair game. Still not kosher in my book, but there is a difference.
(e) At the time of the commission of the act, the victim is at least fifteen years of age but less than
seventeen years of age and the actor is at least ten years older than the victim and is not the spouse of the
victim;
If you're 25, then 15 year olds are fair game.
Again, the 25 year old would be committing sexual assault. A 24 year old, however, wouldn't be. I do agree that that is gross. I do have a 15 year old sister, and couldn't imagine her being with a 24 year old. Though, I do have guns...so I think that would take care of itself. *looks around*
Also, just like every law, there is a catch-all included:
"(b) The actor knows that the victim is incapable of appraising the nature of the victim's conduct..."
Even if the age requirements are legally met, subpart (b) may not have been.