Quote Originally Posted by WES View Post
No, it doesn't *obviously* begin at conception. I could argue that human life begins when the foetus is viable outside of the womb.

If I did you would have no logical counter argument other than 'no it doesn't'. Hence why this is such a difficult issue to resolve.
The meeting of gametes and the creation of a zygote is the sine qua non of life. Life is impossible without it. It is the start point whose usual end point is the birth of a human baby. To try and pretend there is any other point at which life begins is just silly, I'm afraid.