But researchers in Texas, Oklahoma and other states may not be able to take part in what many expect to be a boom in stem cell science, as several state legislatures have moved to ban or restrict the research on the heels of the policy shift.
This week, the Texas senate passed a budget bill that included an amendment to ban the use of state funds for embryonic stem cell research. Earlier in March, the Oklahoma House passed a more restrictive bill -- one that would make it a criminal misdemeanor for scientists to work with embryonic stem cells in the state.
"I absolutely believe that if the federal government messes things up, states have a right to straighten it out," Oklahoma Rep. Mike Reynolds, who introduced that bill, told Reuters. "My motivation is to protect unborn children."
The Texas House and the Oklahoma Senate have yet to vote on the bills. If the legislation passes, Texas and Oklahoma will join several other states, including South Dakota, Louisiana and Arizona, that already have laws restricting or banning embryonic stem cell research.
"Certainly these bills send a statement," says Erin Heath, a senior program associate at the American Association for the Advancement of Science's Center for Science, Technology and Congress, who has been tracking the bills. "It's hard to tell right now what kind of broad impact they'll have. And it's hard to even tell which bills will go all the way."
Indeed, the Georgia Senate passed similar legislation in mid-March -- it would have banned therapeutic cloning in the state and the creation of embryos for any purpose other than procreation. But on Tuesday, state Rep. Amos Amerson, the Republican chairman of the House Science and Technology Committee, said that he was going to table any discussion of the bill and that the House would not vote on it this session.
The efforts have pitted religious conservatives against scientists as well as business leaders who worry that the restrictions could drive away scientific investment.
Former presidential science advisor Neal Lane, now a professor at Rice University in Houston, joined 17 other Texas scientists in writing a letter to the legislature opposing the bill.
"Going down this road puts Texas, which ought to continue to be a world center for medical research, well behind the curve," Lane says.
In Georgia, Rep. Amerson cited economic concerns as part of his reason for tabling that state's legislation, telling the Gainesville Times that he didn't want to hurt the state economically by angering participants in a national bioscience conference that will bring 20,000 people to Atlanta in May.
Irving Weissman, the director of Stanford University's Institute for Stem Cell Science and Regenerative Medicine, says the states that ban stem cell research will hurt themselves economically and scientifically. When California decided to fund stem cell research during the eight years of federal funding restrictions, he was able to attract more money and researchers to Stanford's institute.
"The new industries that spring up from successful research will be in California," he says. "[States] may choose to opt out of this kind of research because they have some moral or religious sense guiding them rather than scientific merit, and it will hurt them."
Even Texas's less restrictive bill, which bans using state funds for the research but does not prohibit it altogether, will have a "dramatic chilling effect," according to Sean Tipton, director of public affairs for the American Society of Reproductive Medicine. That's because "state funds" can be interpreted very broadly -- perhaps even cutting out federally- or privately-funded research done in buildings owned by state universities, for example.
"Research institutions just don't want to risk being on the wrong side of the legislation," Tipton says, "So they tend to make the most broad interpretation possible of these kinds of restrictions."
Conservative groups, meanwhile, say they plan to continue supporting state-level legislation.
"I don't know that we'll have a very big voice [on the federal level]," David Prentice, the senior fellow for life sciences at the conservative Family Research Council, told the New York Times. "The states tend to be a little more fluid."