New report urges guidelines for stem cell-based embryo models

LONDON — Policymakers and scientific groups need to specify guidelines for the burgeoning field that uses stem cells to mimic aspects of embryonic development, including by establishing certain red lines on research, an influential U.K. bioethics group said Wednesday in a new report. 

Specifically, the report from the Nuffield Council on Bioethics says that researchers should not use these stem cell-based embryo models to try to start a pregnancy in a person or animal, and should not develop them to the point that they have the capacity to feel pain or awareness. 

The models that scientists have built thus far remain too primitive for either of those outcomes to occur, researchers say, and it would likely be years before either might even be possible. But in the new — and fast-moving — field, research teams around the world have shown they are coaxing cells to form more complex models, fueling competition among different groups. Governance structures have yet to adapt.