BACKGROUND: The recent derivation of embryonic stem cell lines from human blastocysts and related implications for regenerative medicine has intensified a longstanding debate about the use of human embryos for research purposes. However, studies have shown that few couples with stored embryos opt to donate them for research. Herein, the attitudes and concerns of potential embryo donors to donation of surplus embryos for medical research were examined. METHODS: From a total of 509 couples who had stored frozen embryos and who had received a questionnaire about embryo donations for medical research, 152 women (30%) and 123 male partners (24%) responded. Embryos had been stored for a mean of 2.25 years (range 3 months to 12 years). RESULTS: Some 10% of respondents indicated it probable, and 34% possible, that they would donate their surplus embryos for research in the future. Women respondents whose embryos had been stored longer, and those committed to the practice of a religion, were more worried about their embryos. Respondents positively disposed to donation commented on their desire not to waste embryos, a desire to help infertile couples, and/or to advance scientific knowledge. Those with negative views commented on the embryo as a potential child and expressed concerns about a perceived lack of control over the type of research to be carried out. CONCLUSIONS: Findings indicate a need for tailored education and counselling about embryo donation for medical research.