Okay, this is how I look at it:

Woman have a choice. They can abort, put the baby up for adoption, or keep the baby.

Men have a choice. They don't have to sign the birth certificate. As far as I'm aware, if it's not signed, they're not responsible.
However, a woman can make him take a state paternity test, and then force him into child support.
But if he made the decision to not be a father when the baby was born, and probably before, and the woman decided to keep it anyway, I think it's horrible to then force him to be dragged into it. I only think that's okay if a man talked a woman into getting pregnant, kept saying he'd be the father until she was past the point where she could get an abortion, or until the baby was born, and then bailed.

It really has a lot to do with maturity, but ugh, that's why there's these laws and these arguments... because people who are not mature enough for sex are having babies.
How I wish girls could be forced to get an IUD when they start their periods until they've passed tests proving they're intelligent and responsible enough to conceive... *ahem* But that's a completely different topic.