My opponent keeps skipping the real conflict: not when life begins, but whether one body can be conscripted to sustain another. Even granting a fetus moral worth, we don't force people to donate organs or blood to save someone dying. Pregnancy is that, but longer and riskier. Apparently a fetus gets squatter's rights while the person carrying it gets a legal obligation. That's backwards. The right to control your own body is the whole ballgame.