Hybrid Test Drive
Advances in stem-cell technology cheer and alarm ethics watchers.
Sarah Eekhoff Zylstrad
11/16/2007

While scientists in the U.S. hailed sperm cells as a possible alternative to embryonic stem cells, regulators in Great Britain became the first to approve inter-species experimentation.

The U.K.'s Human Fertilisation and Embryology Authority, which reports to the Department of Health, ruled in September that there was no "fundamental reason" not to use animals as egg donors for the creation of animal-human hybrid embryos. Currently, researchers depend on human embryos from fertilization clinics.

Hybrid embryos are created by scraping an animal's DNA out of its egg and inserting a nucleus from a human cell. Researchers don't know yet if hybrid embryos will display the developmental flexibility that human embryos do. "But the odds are high," said William B. Neaves, president and CEO of the Stowers Institute for Medical Research. "It's worth trying." story art