The father did help make the fetus, but it resides solely in the property of the mother.
But the thing is, when it's in her it's "her choice" but when it's born it suddenly becomes "LIEK HALF HIS OMG!" Even as a pro-choice person I find it disturbing that many women feel as if they have the right for other people to finance their irresponsible decisions.
I'm pro-choice, but I think it should work both ways.
If I were to plant a tree on somebody else's lot (with their permission, of course), could I claim part-ownership of the tree?
If you were paying for it's upkeep, yes.