“It’s not clear how many women will step forward to donate eggs,” says Kevin Eggan, a biologist at Harvard who has sought permission from his university to start SCNT experiments. Eggan says he’s spent much of the last year learning about the ethical and medical issues associated with egg donation. Women must undergo hormone treatments to stimulate ovulation, counseling sessions to understand the risks involved, and a medical procedure in which a needle is inserted into the vagina to remove eggs from the ovary. A small percentage of donors develop ovarian hyperstimulation syndrome, which in rare cases can cause kidney damage or death.

Several states have recently enacted regulations governing stem cell research, hoping to avert the kind of questionable egg donation practices that occurred in South Korea. One of the most heated debates concerns payment for eggs. Opponents of the practice say paying women could lead them to undergo the procedure without fully considering the risks. But others are concerned that laws restricting payment will drastically reduce the number of donors.

The American Society for Reproductive Medicine estimates that egg donation requires an average of 56 hours for all counseling and medical procedures. ACT used to pay donors $4,000 for the procedure. However, a new Massachusetts law, designed to encourage stem cell research in the state, limits reimbursement to expenses directly related to the donation process. It’s unclear if that law prohibits compensation for lost pay; if so, though, it could actually hinder the research, says Lanza.

Lanza says that all the women who recently contacted ACT about donating eggs dropped out of the process when they learned how much time was involved. “I think it’s abuse to subject women to this and not at minimum compensate women for lost wages,” he says.

The California Institute for Regenerative Medicine, the agency that oversees state money designated for stem cell research from Proposition 71, has just adopted a set of ethical guidelines limiting payment to reimbursement for expenses such as lost wages and child care. “It’s nothing in the way of an incentive, it’s simply to remove a disincentive,” says David Magnus, an ethicist at Stanford University in Palo Alto, CA. Magnus says other states should enact similar regulations, so that stem cell lines generated from future SCNT experiments can be shared between states without ethical concerns.

Many scientists, including Lanza and Eggan, are so concerned about the egg-donation issue that they’re developing alternative technologies to create cloned stem cells – alternatives that eliminate the need for human eggs. Those just-emerging technologies, however, won’t be developed anytime soon. “Some tantalizing data suggest that once we understand the magic of eggs, we can replicate it,” says Lanza. “But for now, it’s still a big mystery.”