When Does Pregnancy Begin?

I took a biology class this summer that was about pregnancy, and it covered everything from having sex to giving birth. It was really interesting, but one of the controversial subjects covered was the exact moment when the fetus becomes a living being.

Q&A: Alternative Ways To Get Pregnant Without Having Intercourse

I’ve been married for 3 years and still can’t have sex due to very painful penetration. However my husband and I would like to have a child very, very soon. We are trying to get pregnant naturally by having my husband ejaculate in my vaginal opening so that the sperm can swim through my uterus. Is it possible to get pregnant this way?