They do look all dolled up, don't they?
That is my thought. I think someone is lying about his bio. 
He claims that his homeschooling was an accelerated program. I have heard of that in college or the military, but in home schooling? I doubt it.
From what I know about home schooling (not much, but family friends swear by the practice), there isn't much regulation at the state and local levels on it -- which is good when you're of a conservative bent and you don't need your hand to be held by the fed, state, and local whackjobs that think they know more about your kids than you do.
So accelerating through a home schooling program is definitely doable and achievable. It's strictly on the parent/tutor and the student as to how quickly they can get through the information.
I dunno about the Doogie Howser thing. I always thought he was the original metrosexual whose 'nads hadn't yet dropped.