Nearly six in 10 Americans support loosening restrictions on federal funding of stem cell research. Proponents of stem cell research say Obama's order is a promising sign that progress can be made after a more-than-eight-year stalemate, while others say it is only a tiny step. Anti-abortion groups say the research is unethical and unreliable.
Lamberth had originally dismissed the case, saying the plaintiffs lacked standing to sue the government. An appeals court reversed that decision, agreeing to hear the case and forcing Lamberth to reconsider a request to issue a temporary injunction.
ABC News' Jason Ryan contributed to this report.