Science is not in the business of creating moral judgements, and any attempt to do so is in the first place just not science, and is in the second place [u][i][b]ALWAYS[/b][/i][/u] based at some point on arbitrary, baseless assumptions. That's why it should be done the other way around. The issue is, morally speaking, what kind of an organism are we ok with destroying, * and whether such an organism has nearly or exactly the same traits (that we consider important) as a human at some stage of development in the womb. Once we have settled on the first part, the morality, the biology is the easy bit, because once we've decided that (for example) we can kill organisms with no sense of pain or consciousness, we can pinpoint that part of a developing foetus and allow ourselves to abort from then backwards. Attempting to create morality from the science makes the false assumption that morality CAN be created from science, when in reality all it does is lend weight to one side or the other of a pre-existing morality. Survival of the genes might be advantageous for an organism, for instance, because it ensures survival of the race, but that the race 'should' survive is a human construct. Most races don't survive very long in the context of the planet let alone the galaxy or the universe - that's just as much science as the drive to reproduce - yet we feel it more moral to keep the race surviving over following the rule of 'well we all gotta die someday' because... [arbitrary baseless assumption]. *Please don't say you aren't in favour of destroying 'any' organisms. A weed is an organism. If you take it out of the ground you have destroyed an organism. A carrot is an organism. If you eat it and digest it you have destroyed an organism. The argument is 'when' an organism stops being something we disregard like that.