Known as the Dickey-Wicker amendment, it has been included in the annual appropriations bill for the Department of Health and Human Services every fiscal year since 1996.

The amendment says, in part: "None of the funds made available in this Act may be used for—(1) the creation of a human embryo or embryos for research purposes; or (2) research in which a human embryo or embryos are destroyed, discarded, or knowingly subjected to risk of injury or death."

Close observers on both sides of the embryonic stem cell issue were well aware of the Dickey-Wicker amendment, and understood that it would pose a legal obstacle to federal funding of embryo-killing research even if President Obama issued an executive order reversing President Bush's administrative policy denying federal funding to that research.

“For the past 8 years, the authority of the Department of Health and Human Services, including the National Institutes of Health (NIH), to fund and conduct human embryonic stem cell research has been limited by Presidential actions,” said the order that President Obama signed Monday. “The purpose of this order is to remove these limitations on scientific inquiry, to expand NIH support for the exploration of human stem cell research, and in so doing to enhance the contribution of America's scientists to important new discoveries and new therapies for the benefit of humankind.”