Being a middle school science teacher, and a good ol' southern church boy, i definitely have thought about and been asked about this topic often. After multiple discussions, debates, ect., I have decided that this is how i feel.
The creation of life begins at conception (thats the church boy in me). The problem with the stem cell research topic, is that stem cell research itself is not why people should be upset, even though it is. The actual problem is in vitro fertilization. This is why.
When a woman undergoes ivf, a doctor basically extracts a large number of her remaining eggs from her woman parts. These eggs are the splashed with sperm from a doner, and several embryos are created (which i again view as life). The doc then takes anywhere from 1-8 of the best looking embryos, and inplants them in the female and hopes that they take. Even if he implants 8, none of them could take, or all 8 (a la octomom). Heres why ivf is the real problem. If the eggs take, then the doc stores the remaining embryos in a freezer until the woman decides that shes done reproducing. The doc then essentially throws the embryos out, killing them.
Stem cell research takes those already condemned embryos, and does something useful with them. The research does kill the embryo, but it would be dead anyway, since the doc throws them away. So being that that is the situation, i dont have a problem with stem cell research, but I do have one with in vitro fertilization. I wish more people who slam stem cell research would think about that.......