While I appreciate your point, there are significant differences. First, embryonic stem cells have zero chance of becoming a human being. The atrocities committed under Nazi rule were eventually stopped and survivors bound for those atrocities were freed. Stem cells have no such possibility. Two, there are those around us know who are technically alive but suffer horribly – not at the hands of their mortal captors but at the hands of their own genetic defects or a physical tragedy. You can take something bound for disposal at turn it into freedom from suffering and a potential for a fully utilized life. I see this as identical to the organ donor program. You can put those organs in a casket or urn or you can give someone a chance to live their life. No matter your decision, the donor has the same fate. The only question is, do you spare someone else's suffering?