A point (Dr.) Tom Coburn, who has been a great boon to this debate in the Senate, makes on his website :
Proponents of destructive embryonic stem cell research claim that surplus embryos “are going to be discarded anyway.” A RAND study has found that to the contrary, very few embryos are expected to be discarded. The vast majority—88.2% are designated for family building and another 2.3% are being donated to other families for adoption. According to the RAND study, embryos available for research do not have high development potential and very embryonic stem cell lines could be created from the embryos available for research. This means that embryos would have to be created specifically for destruction is additional stem cell lines were to be created for research.