As I explained above,  it is not "religious intolerance" to say that "an innocent human being's right to live cannot be dependent on the religion of the person who asserts the right to take that life away."  The question is not whether the life taker is Jewish or Christian, but whether this this thing whose life is to be taken is human.  

You say that the idea that life begins at conception is relatively recent.  That, for one, is irrelevant.  The same could be said two weeks after it was learned that the world is not flat.  What's relevant is that as time progresses, and we learn more about the development of life in the womb, we have more basis than ever to say that human life begins at conception, rather than at, say, quickening.