Earlier this week, the Stem Cell Research Enhancement Act of 2007, which would loosen the restrictions on human embryonic stem cell research in the US, passed in the US Senate.

Under the existing policy, federal funds may be used to study only those stem cells taken from embryos destroyed by Aug. 9, 2001 -- or about 21 of the nearly 400 stem cell colonies created since 1998.

The House-based bill would expand that pool of available cells to include those from any of the thousands of embryos that are discarded by fertility clinics each year, as long as those cells were freely donated for research by the parents. It would also impose some of the country's first ethics rules on embryo research.

You can see the full text of the bill here, and track the current status here. More from the Washington Post.