The official could not confirm the details of what Obama would sign, but advisers had previously said he favored lifting the eight-year limitation on funding of human embryonic stem cell research imposed by his predecessor, President George W. Bush.The issue is controversial because some people believe the destruction of any human embryo is wrong.
The official also said Obama would make an announcement about a broader initiative to restore scientific integrity to government processes.
Other government officials, who asked not to be named, have said Obama could take several different routes to lifting the Bush limits on stem cell research. These include an executive order, a simple statement of policy, or some kind of joint action with Congress.
Obama has made clear since before he ran for president that he supports federal spending on human embryonic stem cell research.
Stem cells are the body's master cells, the source of all cells and tissue, like brain, blood, heart, bones and muscles. Embryonic stem cells come from days-old embryos and many scientists consider them the most powerful because they can transform into any type of cell in the body.
Doctors hope to harness the transformational qualities of stem cells to treat a variety of diseases, including brain cells for Parkinson's disease, pancreatic cells for diabetes and nerve cells for spinal-cord injuries.
Scientists have complained that the eight years of limitations placed by Bush have held up research, while opponents of human embryonic stem cell research say scientists can be working with other types of stem cells that do not come from embryos.
DICKEY AMENDMENT
U.S. legislation called the Dickey Amendment forbids the use of federal funds for the creation or destruction of human embryos for research.
In 1998, soon after human embryonic stem cells were discovered, the Health and Human Services Department determined that the Dickey Amendment did not apply to researchers working with human stem cells, so long as they did not get the cells themselves from embryos.
But in August 2001, Bush declared otherwise and limited the use of federal funds to human embryonic stem cell lines, or batches, that existed as of that moment. He vetoed congressional attempts to override this decision.
Several members of Congress who oppose abortion rights have supported broader federal funding of human embryonic stem cell research, and the issue crosses the political divide.
Even many abortion opponents say they support the use of stem cells from embryos created in fertility clinics -- embryos that would otherwise be discarded.
Critics of the Bush administration accused it of inserting ideology into the scientific process -- from the stem cell issue to climate change and even contraception. The Obama administration has been working to overturn these policies.
On Friday, the Health and Human Services Department moved to rescind a controversial rule, made final just before Obama took office, that would allow healthcare workers to invoke their consciences in refusing to provide health services or information to patients.