When did I question the scientific definition of life?
Fact is, there wouldn't be a big question if abortion weren't at the basis of the discussion but that's another matter.
My question to you is from a morality standpoint. Simply subscribing to the legal definition of life doesn't absolve you from the moral standpoint.
When sperm meets egg, what happens virtually all of the time? I'll give you a hint, a baby is produced. That is where I morally draw the definition line. At no time does a human life not occur when sperm meets egg.
Unless you're masturbating over a petri dish full of human eggs, I'll go out on a limb and say you're morally OK from an ending human life standpoint. That's common sense, it shouldn't have to be explained to an intelligent adult.
So let me ask the unanswered question again - how can you morally defend the murder of an unborn child?