Should scientists be allowed to use human embryos left over from IVF for stem cell research if it could lead to cures for diseases like Parkinson's? I've read that thousands of embryos are discarded each year because they're not implanted, and using them for research seems more respectful than simply throwing them away. But I can't ignore the moral weight of creating life for utilitarian ends, even if the embryos are only a few days old and would never become a person. My own view swings both ways: I once felt it was clearly justified, but after talking to a bioethicist, I now doubt whether the ends justify every means. Do you think the potential medical breakthroughs outweigh the ethical concerns?