When Does Human Life Begin?

A hard puzzle in abortion policy is when "human life begins". Is a one-celled embryo a human? Is an 8-month fetus a human? Is a 2-year-old a human?

How about if we approach the question from the other end. When does human life end? When is someone dead? It could be when his heart stops, but people do get revived often from that state and we don't call it resurrection. It could be when his brain activity stops, and I think that is the common criterion.

If the criterion for lack of life is lack of brain activity, then the one-celled embryo is not alive. Rather, we need to ask when a brain begins, and when it becomes active. A pro-abortion blog that discusses the brain criterion says that brain activity starts much later than the brain itself is formed, at 21 weeks, which is 5 months. The same blog says anti-abortion people claim the time is 10 weeks (which sounds more plausible to me, and even rather late).

November 18. Another approach would be to ask when an embryo has blood. Blood has special significance in the Bible. This webpage doesn't mention blood specifically, but it implies the embryo has blood somewhere in the 8 to 21 day range. There is a brain at 29-35 days, and brain waves at 40 days. In Arizona, at least, in 2007 of 10,486 abortions, 3,032 were at 6 weeks (42 days) or less. 102 were at 21 weeks or more.