You wrote, "If a couple agrees to destroy 8 cells in a petri dish, it's far different from having an abortion". And if someone murders a one day old baby, that's "far different" than murdering a 30 year old. But so what? Human life is human life, in all its forms, at all stages of development.
Yes, I wrote those things. There are lots of philosophical issues to explore here and I haven't done much thinking about them. Here are some questions for anyone who's interested in trying to tackle them:
1) How is human life different from any other kind?
2) Does a newly fertilized (human) egg have a soul?
3) Is there a moral equivalence to letting some fertilized eggs in a petri dish die through inaction, and having an abortion?
4) Why is human life sacred?
I would be interested in any and all answers from any perspective.