OK, so I've been thinking about this for some time.

My original thought was that a father of an unborn child could bring legal action to stop an abortion from happening, as it is his child as well as the mother's.

Turns out this has been tried before and was thrown out, as apparently Roe V Wade is predicated on the woman being free to do "with her own body" as she sees fit.

So then I thought, can we not then bring science to bear on the subject, and via DNA testing of the embryo/fetus clearly show that indeed the life now in the womb is genetically seperate from that of the mother, thereby making it not "her own body", and thus nullifying her "right" to do with it as she pleases?