Almost half of Spanish couples recently asked to donate their excess embryos to stem cell research did so.

The response of 97 couples who had undergone in vitro fertilization treatment at two Spanish clinics contrasts sharply to the situation in the United States, where a 2003 review found that just 3 percent of surplus embryos were going to stem cell research.

In the Spanish study, 49 percent of couples agreed to donate their embryos to that type of research, 44 percent decided to keep their embryos on ice indefinitely, 7 percent gave their embryos to other infertile couples, and less than 1 percent decided to discard their embryos, according to a report published online in the June 7 Cell Stem Cell.

In-depth briefings from an embryologist and a lawyer prompted the high donation rate, say Pablo Menendez and his colleagues at the Spanish Stem Cell Bank in Granada and Madrid.

Couples learned about specific research projects for which the embryos would be used and received counseling on relevant legal issues. The authors say that the briefings were unbiased but that 2 hours of “personal attention could be a persuasive factor” in convincing couples to donate.

Also, the couples had undergone in vitro fertilization at least 3 years prior to the interviews, and a third of the women had successfully given birth, “circumstances that make the decision to donate surplus embryos for research more appealing,” say the authors.

An in vitro fertilization attempt typically produces a half dozen or more excess embryos. In the United States, some 400,000 such embryos remain in deep freeze. In Spain, some 100,000 excess embryos exist.

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