The structures aren’t embryos, but scientists nevertheless didn't let them grow past two weeks in deference to longstanding ethical guidelines.A blastoid is a model for a blastocyst, a ball of cells that form within a week of fertilization and are about the width of a hair....
At that point, he said, the collection of cells didn’t reflect a 13-day-old embryo; they weren’t growing enough or organizing as well.He said ethical concerns also came into play: For decades, a “ 14-day rule ” on growing
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2021-12-02 00:00:00.0