I mean you have four situations:
1) neither parent wants to keep it. Great, everyone but the conservatives are happy.
2) They both want to keep it. Great, everyone is happy (unless it ends up being a girl and they live in China)
3) The mother wants to keep it but the father doesn't. The mother can go ahead, give birth and legally force the father to help pay the resultant bills (in general)
4) The father wants to keep it but the mother doesn't. Well he's shit outta luck.