A young grade school child was given an assignment to write an essay about the start of life. So off he went and asked a Catholic priest: “Father, when does life start?” Of course, the answer he got was that it started at the moment of conception.
He then approached a Baptist minister with the same question. The answer he received was that it started at the moment of birth.
He then went to a Rabbi and asked the same thing. The old Rabbi thought about it for a few seconds and then said to the child: "Life begins when the last kid leaves home and the dog dies!"
Ha a nice story - I think my Dad could well identify with the Rabbi!! If you want my opinion, the point of life is probably when the conceptus can no longer be split into twins. Before that point, you can't logically think of the ball of cells as an individual, so it can't really be alive in my opinion. I think this is at about day 14 of pregnancy in humans.