Researchers break record for keeping lab-grown human embryos alive

Research gives glimpse of critical period of human development, sparking calls for debate on current 14-day legal limit for embryo experimentation

Researchers have broken the record for growing human embryos in the lab, keeping them alive and active beyond the stage when they would naturally implant in a mother's womb.

The feat has been hailed as a milestone in the field, but the work by two teams of researchers in the US and the UK puts scientists into direct conflict with a decades-old law that prohibits donated embryos from being grown in the lab for more than 14 days.