Scientists also have highly unrepresentative personalities, high in openness to experience, and tend not to care about conservative values like respect for authority, group loyalty, and various taboos .Delegation of decision-making power to representative samples of elite scientists will thus favor those values more than the policies that would be adopted by a set of comparably informed people with values representative of the population.

This is a good summary of the bioethicists' argument; but I find their argument unconvincing. My suspicion is that the values of "comparably informed people" would inevitably tend to resemble those of scientists -- at least for practical purposes.

Concretely, for instance, it seems that much if not most of the opposition to embryonic stem-cell research is based on a failure to grasp the empirical fact that personhood resides in brain structure: no neurons, no person.

Maybe in principle there could still be moral arguments worth having that don't directly depend on the science; and maybe scientists would be biased toward certain stances in such arguments. But I don't think that's what's really going on here.