Rushing to work at Cincinnati Children’s Hospital Medical Center one recent morning, Jason Spence, 33, grabbed a moment during breakfast to type “stem cells” into Google and click for the last 24 hours of news. It is a routine he has performed daily in the six weeks since a Federal District Court ruling put the future of his research in jeopardy.

“It’s always at the front of my brain when I wake up,” said Dr. Spence, who has spent four years training to turn stem cells derived from human embryos into pancreatic tissue in the hope of helping diabetes patients. “You have this career plan to do all of this research, and the thought that they could just shut it off is pretty nerve-racking.”

Perhaps more than any other field of science, the study of embryonic stem cells has been subject to ethical objections and shaped by political opinion. But only a year after the Obama administration lifted some of the limits imposed by President George W. Bush, a lawsuit challenging the use of public money for the research and a conservative shift in Congress could leave the field more sharply restricted than it has been since its inception a decade ago. At stake are about 1,300 jobs, as well as grants from the National Institutes of Health that this year total more than $200 million and support more than 200 projects.

The turn of events has introduced what researchers say is unprecedented uncertainty to a realm of academic science normally governed by the laws of nature and the rules of peer review.