Lanza says the new method for growing embryonic stem cells is consistent with current practices used in IVF clinics, which often extract a cell from an pre-implanted embryo in order to perform pre-implantation genetic diagnosis (PGD). “Normally the cell is taken in the IVF clinic and used immediately for testing,” Lanza explains. “What we’re saying is, let it grow overnight, there is still time to do the test and implant the embryo, and then use the rest of the biopsy for stem cell generation. It doesn’t change the outcome of the test, it doesn’t present any other risk to the embryo, and it ensures that there is a cell line out there that matches the child and his or her siblings.”
That scenario could be limited, however, because only a small percentage of embryos used in IVF clinics actually undergo PGD. “We would certainly not recommend that IVF with PGD should become routine in order to generate a stem cell line for each individual,” says Zev Rosenwaks, director of The Center for Reproductive Medicine and Infertility in New York City. “Other than that, the procedure seems like a perfectly reasonable proposition for cases when PGD is already being performed.”
According to Rosenwaks, only 5 to 10 percent of all IVF subjects undergo PGD for specific genetic and chromosomal disorders. There is no evidence that children born from PGD embryos are harmed by the procedure.
Lanza’s work could advance the field by removing the ethical barrier of embryo destruction. “This would be a serious and profound breakthrough for those involved in the science of stem cell research,” says Laurie Zoloft, director of bioethics at Northwestern University’s Center for Genetic Medicine. Those opposing stem cell work because it requires the destruction of embryos “now will be able to support this research.”