The British government has reversed its stance on the creation of human-animal hybrid embryos and will propose allowing scientists to use them as sources of stem cells. Scientists developing treatments for incurable diseases would be allowed to grow the hybrid embryos for no longer than two weeks, and implanting them into a human womb would not be permitted.
The proposal marks a turnaround for the government, which last year proposed a complete prohibition on hybrid embryos. It would continue to forbid the creation of so-called true hybrids, which involves fertilizing a human egg with animal sperm or vice versa. The medical community agitated for the new regulations, which drew the ire of opponents of stem-cell research and abortion. (Read more hybrid animal stories.)