kengr

The problem is this.. the logical point to decide when life begins, is when the fetus is independently viable. But, this is a problem because that point keeps changing, being revised downwards as medical technology improves.

The heartbeat and brainwave arguments were advanced in an attempt to perform an end run around this problem by defining it based on developmental stages which would be fixed and could be reasonably argued without which there is no personhood. Sort of an improved version of defining life beginning at the 'quickening' stage.

But that fell flat because it was based on flawed medical assumptions, as you point out. Not to mention we can't even measure brainwaves in utero, and have no understanding of how they relate to whether or not the fetus is a person...

As for the problems surrounding regarding life beginning at conception... well that's less a bug and more of feature, as it was put forward by those who wanted that specific licence to prosecute women, and use it as an excuse to ban abortion outright.

I would personally argue that potentially life begins shortly after implantation, around about the time or just after, we can be reasonable sure that the fetus isn't going to be rejected. But that argument is irrelevant.

Because I would also argue that unless it can be definitely proved that the mother engaged in behaviour known to put the developing fetus at risk (smoking, drinking etc) then any miscarriage should not be investigated as or treated as deliberate homicide. Babies are fragile, and natural deaths occur at any stage up to and including birth.

But... that's probably far too sensible for this reality.