The court also scheduled oral arguments for March in two cases over state laws on same-sex marriage.

Without comment, the court let stand an August ruling by the U.S. Circuit Court of Appeals for the District of Columbia which dismissed a lawsuit by two scientists who said the funding policy inhibits their chance of getting government grants for their research on adult stem cells, and argued that violates another law.

Under a 2009 policy, the government began allowing federal funding of research on human embryos that were created for in vitro fertilization but were no longer needed for that purpose. Under a previous policy, government funding was allowed on stem cells derived from a handful of lines that existed to that point.

The two scientists, Dr. James Sherley and Theresa Deisher, sought to block the expansion, arguing that it was barred under a 1996 law, known as the Dickey-Wicker amendment, that prohibits use of federal funds for "the creation of a human embryo or embryos for research purposes" or "research in which a human embryo or embryos are destroyed, discarded or knowingly subjected to risk of injury or death greater than that allowed for research on fetuses in utero."

In his August ruling, Chief Judge David B. Sentelle of the D.C. Circuit, said the National Institutes of Health's interpretation of the Dickey-Wicker amendment was "reasonable" in permitting funding of embryonic stem-cell research using cells derived using private funds. Sentelle said the funding guidelines promulgated by NIH in 2009 correctly and legally allowed funding on stem cells derived from embryos created for artificial insemination and donated to scientists after the parents decided to discard them.

The Catholic Church opposes stem-cell research that destroys human embryos. The same objections do not arise over research using adult stem-cell lines, because these are cells taken from anyone after birth.

The court the same day announced that oral arguments would be heard on consecutive days in March in cases over same-sex marriage laws. On March 26, the court will hear arguments in Hollingsworth v. Perry, which considers California's Proposition 8, which bans same-sex marriage. On March 27, it will take up United States v. Windsor, which weighs the constitutionality of the federal Defense of Marriage Act, which defines marriage as between one man and one woman.