Similar regulations exist in California, and guidelines from both the National Academy of Sciences and the International Society for Stem Cell Research permit only limited compensation for egg donors. "Compensating egg donors was a very contentious issue for the International Stem Cell Society," says George Daley, president of the society and a scientist at Children's Hospital Boston, who is also attempting human therapeutic cloning. "We felt that paying the same market rate as ART was not acceptable, but we did agree on a token amount, in part to recognize the time, effort, and suffering."

The United Kingdom has taken a different tack. Last year, the regulatory board that oversees embryonic stem-cell research in the United Kingdom approved an "egg sharing" program, something that some scientists and ethicists want to see adopted in the United States.

Women who plan to undergo in vitro fertilization (IVF) agree to donate to research any excess eggs gathered during the procedure in exchange for subsidized medical costs. "I favor it because it grants access to IVF to the poor, who have traditionally not had access to expensive IVF procedures," says Laurie Zoloth, director of the Center for Bioethics, Science and Society at Northwestern University, in Chicago. She adds that this eliminates one of the major ethical objections to egg donation: that women will put themselves at risk for no personal benefit or will feel coerced to donate eggs because they need money. "In this case, people would be doing it for personal reasons," says Zoloth.

Eggan says that he was looking into trying a similar approach at Harvard but was advised that state laws prohibit it.

In the meantime, scientists are exploring various alternatives, including the use of animal eggs in place of human ones. (See "Human-Animal Cybrids.")