For more than 30 years, scientists have followed a rule they imposed on themselves to avoid growing a human embryo in a lab dish for more than 14 days.
Until recently, the "14-day rule" was largely academic. Scientists couldn't grow them for that long if they wanted to.
But in 2016, two teams of researchers reached 12 days, and in 2019, another group grew monkey embryos for 19 days.
These advances have spurred some scientists to argue in two recent papers that the 14-day rule should be modified or dropped. There's a lot to be learned by pushing embryos out to 28 days, they say.
The regulatory committee of the International Society for Stem Cell Research, which lays down guidelines for the scientific field, has been debating the issue for months and is expected to issue its final decision this month.
Some ethicists and scientists are concerned that revising the rule just as it becomes technologically feasible to break it is ridiculous and morally repugnant.
"If you abandoned every rule or law that inhibits you as soon as it inhibits you, we'd live in a lawless world," said... see more