If I can add to that, one of the things that's absolutely true—and there are a number of us funded to do research around the concept of the healthy embryo, what constitutes a healthy embryo, and what is an embryo that is or is not suitable for freezing or transfer—is that we find that because it is too much dependent on the expertise of the clinician or the embryologist, etc., you do get variety in terms of how you go about thinking and scoring when you're not looking at a genetic anomaly but are looking at some metabolic or other considerations.
One other important thing is that there was a study done by Tekpetey, presented in 2003. If I'm not mistaken—and you might know this—I think he won the prize that year, showing that what would be described as ugly embryos—morphologically, they're not very nice—turn out to make beautiful babies. He actually showed that some of the criteria that are used to make those determinations may not be as tight as we might have thought.