And this is where the arrogance of certainty rears its ugly head. I am speaking specifically to Don and bobad with that one. The idea that only yours is the informed position, and speaking in what appears to be condescending terms (as an example:As Don has pointed out some knowledge of embryology is required to make an informed choice on the issue and overcome the emotionality connected with using loaded words.) Let me assure you both, I have a knowledge of what you quote, and had it before asking the question. I have a personal bias in wanting this technology to continue and advance, as I suspect you both do. But the ethics need scrutiny. And the questions are of such importance that they should be respected by all who take part in this debate.

The question which troubles me goes to a point before the point that the two of you are referring to. Undifferentiated cells or not, once fertilization has occurred, everything is in place. All that is required is the implantation. The fact that one chooses not to implant does not take away from the fact that a fertilized embryo is there. It is only by a deliberate act that the cycle doesn't go on. As to Jeri's question of the use of the excess embryos, I believe they absolutely should be used, but I have the same concerns about the procedure which creates these excess embryos in the first place. Yet her point of "greatest good, least arm" certainly applies.

bobad, your contention that a researcher should be allowed to just pursue on the basis of his or her own sense of ethics just doesn't hold water, IMO. Society has always had ethical conventions. These should be arrived at by debate among ethicists and ethical researchers, and would be considered norms. The standard you suggest would lead to anarchical (is that a word? LOL) research, where all bets were off. I am sure you can look historically at regimes who already did that and they are viewed as monsters.

Mick