First of all, sorry for your losses. Those events must have been very difficult and I hope this finds you and your family well.
On to the point. The point (in a timing sense) of "humanity" is, at base, a religious argument. For ancient Jews, the first breath in life was said to impart the soul, for some modern Christians, life begins at conception. St. Thomas Aquinas wrote on the fetal brain achieving enough "complexity" to accept a human soul (which he believed occurred around the 24th week) but the modern Catholic Church has chosen an approach similar to yours, i.e., the point of "humanity" is unknown, so it is better to assume it is at conception than risk being "wrong" in the eyes of God.
But there is some science that goes "against" this, in a fashion. We know, with scientific certainty, that the majority of conceptions do not go on to a viable pregnancy. Many fail to implant, and others are lost too early to be detectable, or mistaken for a simply "late period". Should we mourn each of these? Should we provide burial and religious ceremony to the products of each woman's menstrual cycle each month to be certain not to ignore the loss of a human life? Certainly not. So the question remains, when is a human human? We all agree that the infant, born and breathing on its own is human, and we all agree that the unfertilized egg in a woman's ovary is not uniquely human of itself, so when does the change occur?
The answer cannot be established without faith, because the central component of the question (the definition of humanity) is faith based. And, in this country, we have fought and died for the right to make decisions of faith on an individual basis. I think there exists a middle ground in the abortion debate that is not often discussed. That is, the personal belief that abortion is wrong, but the acknowledgment that this belief is personal, and a matter of faith, and therefore each woman should have the right to decide for herself. Until abortions are mandated or forced onto a woman against their will, that is, in fact, what this debate boils down to. Is an individual in our society allowed to make a decision of faith of their own accord?
Before someone responds to this post with some drivel about how murder is against most religions but it is also against the law, realize that argument is false on two fronts. First, murder is against the societal good, so there are reasons beyond faith to prohibit it. No one has yet made a non-faith based argument as to the societal detriment to abortion. And this leaves out the fact almost every major faith (with some exceptions) allows for killing another person under conditions that would be illegal under U.S. law, so our laws against murder are not based on religious faith. Second, some religions hold very different (and some would say abhorrent) views regarding other major crimes that we would never accept as law here (e.g., the rape of a child is o.k. as long as her attacker marries her and pays her father a dowry) so why legally settle the matter of abortion on a faith basis? If we were to begin legislating on faith, we would live in a very different society...
