Actually birth is the point when a the fetus becomes a baby. It's not that pro-abortion groups can not define it, it is that it is irrelevant.
Location dictates personhood? Does a woman own you penis, once you put it inside of her? Can she destroy it while it is there?
It is not simply a location. It's not as if a full baby magically appear inside a woman the day after conception. The actual person is growing a fetus. The woman is the person.
