Stem cell scientists throughout the US rejoiced last year when President Barack Obama signed an executive order effectively giving the green light again to human embryonic stem cell (ESC) research after close to a decade of funding restrictions. But that celebration may have been premature.

A US district court today issued a preliminary injunction halting federal funding of human ESC research, ruling that such research involved the destruction of embryos, and, thus, violated the “Dickey-Wicker Amendment” to the bill that funds the Department of Health and Human Services.

The Obama administration had argued that ESC research, in which cells are taken from embryos created for in-vitro fertilization that would otherwise be disposed of, does not itself lead to the destruction of embryos.

But in agreement with the coalition of groups, including several socially conservative Christian organizations, that filed the petition, Judge Royce Lamberth rejected this argument. “Simply because ESC research involves multiple steps does not mean that each step is a separate ‘piece of research’ that may be federally funded,” he wrote in a 15-page ruling. “If one step or ‘piece of research’ of an ESC research project results in the destruction of an embryo, the entire project is precluded from receiving federal funding.”

The Justice Department told AFP it was “reviewing the judge’s decision” before deciding whether to appeal the injunction or wait until the full lawsuit is heard in court.