How many unused embryos are there?
According to a survey conducted by Rand Health in 2003, there are approximately 400,000 such embryos in storage in the United States . (Source: Hoffman, D.I., et al. 2003. Cryopreserved embryos in the United States and their availability for research. Fertility and Sterility 79: 1063-1069.) Most of these embryos will never be used for fertility treatment (either because the parents are successful in having the children they want or because treatment is unsuccessful). According to the study, about two percent of these excess embryos are offered by the parents for adoption to create pregnancies in biologically unrelated mothers. Many parents are uncomfortable and unwilling to offer their excess embryos for adoption and would prefer to simply discard these embryos or to donate them for medical research that could help people. The bottom line is that there is no conflict between the adoption of embryos by biologically unrelated parents and the use of embryos for medical research: if all of
