Write your Congressman. At this point in time abortion is legal, the woman carries the child and she gives the birth.
It's completely impractical for a man to insist that a woman bear a child if she doesn't want to. I'm not saying it's right, I'm saying that's the way it is. You could get a judge to say that, yes, she must have the child, then give it up to you. But how will you ensure that she doesn't do something to harm it? "Take that, you bastard - how's a little fetal alcohol syndrome grab ya? Have some heroin, baby!"
Blame biology. You can't give birth - women can. It's just the way it is.