U.S. President Barack Obama has lifted restrictions on federal funding for medical research using human embryonic stem cells. Mr. Obama says it is part of a broader effort to limit political interference in science.

Unlike adult cells which have specific functions, stem cells from very early embryos have the ability to grow into any tissue in the body. Scientists say embryonic stem cells hold the promise of cures and treatments for diseases and conditions ranging from diabetes to paralysis.

But opponents say because a days-old embryo is destroyed in the process, stem cell research is unethical, and amounts to the destruction of human life.

In 2001, then President George W. Bush put limits on federal funding for human embryonic stem cell research. President Obama says that move was wrong and based on, what he calls, a false choice between sound science and moral values.

"In this case, I believe the two are not inconsistent," the president said. "As a person of faith, I believe we are called to care for each other and work to ease human suffering. I believe we have been given the capacity and the will to pursue this research - and the humanity and conscience to do so responsibly."

The president signed an executive order lifting the restrictions at a White House ceremony attended by scientists, patient advocates, and members of Congress.

He also put his signature on an accompanying memo designed to shield science from political interference.

The move was welcomed by Dr. Irving Weissman of Stanford University - a pioneer in stem cell research.

"The Bush administration brought in political requirements that you do not do certain types of research because of their politics, or the ideology, for some their religion," Weissman said. "That is absolutely unprecedented in American science."

But critics of the decisions say there are other options available to researchers besides embryonic stem cells.

David Prentice is with the Washington-based Family Research Council. He cites new efforts to transform adult stem cells to give them many of the qualities of embryonic cells.

"Using embryos (is) old science, bad health care. It is the adult stem cells that actually help patients now," Prentice said.

In making his announcement, President Obama said the government will support promising research of all kinds. He said it is time to make up for lost ground.

That is welcome news for Carl Robb. He has Parkinson's Disease - a degenerative disease of the central nervous system.

"This is going to allow the best and the brightest to do the work that needs to be done and has not been done for so long," Robb said.

The president's announcement did not address a related issue, whether or not to lift the ban on federal funds for research on embryos themselves. The ban, put in place by Congress, bars the use of tax dollars to create human embryos in a laboratory. (SIGNED