It's the woman's call given that it's her life and her health that is being put on the line.
So wait, it's a two person situation when it comes to the responsibility of caring for the baby, but when it comes to extinguishing the life of that baby, the mother has the sole decision?
For better or worse, that's the way nature arranged it. Trust me, many women would be happy for men to bear that particular privilege. When men begin carrying babies, I'll be the first to defend their right to make the choice of whether or not to carry that pregnancy to full term.
A man's choice is who he chooses to have sex with, after the act, he no longer has the final say on what happens to a body he doesn't live in.
The father also has an emotional and practical say in what happens to that baby, because what is inside her womb has his DNA also.
If a man shares the responsibility of raising the child, then he also shares the decision of whether or not that child, or potential child lives.
Obviously, if the mother is at risk of death, then yes, that would put the decision in her hands, but in the case of a child that can be brought to term without risk, then he has as much say as she does.