If you believe that:

a) forcing a woman to have a child she doesn't want is wrong
b) women who make the uni-lateral choice to have a child are entitled to benefits for the burden of having a child

it makes sense that a man who has a child against his will, by someone else's choice, should be entitled to even more benefits, right?

Or to break it down even more simply:

a) forcing a woman to have a child she doesn't want is wrong

b) forcing an unwanted, unnecessary, expensive burden on someone entitles them to compensation

c) doing something wrong and emotionally traumatizing to someone entitles them to seek payment for their emotional damages alone

Most people agree with all of the above, but completely backtrack if you switch the genders. It's just lunacy to me that forced-fatherhood is still considered to be something the man should pay for. It's an outdated system that is in and of itself sexist and if you are in favor of equal rights, you should want equal rights and responsibilities when it comes to the decision to have children.

People always want to focus on the fact that yes, her body is the pregnancy vessel, so it is her right to choose. I agree that the act of legally forcing a woman to evacuate her womb is a violation of her rights. But there are plenty of things where physically forcing you to do them would be a violation of your rights, which you should still be held liable for neglecting to do. If you don't think abortion is wrong, then this situation shouldn't be different from you choosing to adopt a problem dog and then having to pay when it kills the neighbor's livestock. It's an emotional cause to you, but you wanted it, and it caused expensive problems for other people. Now it's on you to pay them back.