Worth of human life varies

In two recent letters to the Herald Phil O’Connor seems to equate human life with human personhood. However there has been from the Middle Ages to this day much disagreement about when a human being becomes a human person. In February 2006, Malcolm Turnbull, a recent Catholic convert and currently Leader of the Liberal Party of Australia, said in the Federal Parliament:
"It seems to me that our society has already reached a conclusion to the effect that an embryo at this very early stage is more in the nature of a potential than an actual human being and that the rights of this microscopic bundle of cells are not equal to those of a foetus, let alone a newborn baby."
Surely our more secular New Zealand society must also recognise that the worth of human life varies. Otherwise we would equate a microscopic bundle of cells with a child or adult; we would ban abortion and IVF; we would fight to save the life of every foetus no matter how horribly handicapped; we would seek to prolong the life of the terminally ill no matter how insufferable their pain. We do not follow O’Connor in any of these things because his viewpoint is absurd.