United States President Barack Obama has lifted some restrictions on federal funding of human embryonic stem cell research.
Critics argue that a ban imposed by President George Bush in 2001, has hampered American progress in a host of vital scientific research projects.
US law limits the use of federal money to make human stem cells, but President Bush tightened the restrictions even further to include work using such cells.
Aides said Mr Obama would give the National Institutes of Health 120 days to come up with guidelines.
Dr. Harold Varmus, a former NIH director who is also president of the Memorial Sloan-Kettering Cancer Center in New York, said the NIH will take into consideration guidelines from the National Academy of Sciences and the International Society for Stem Cell Research.
