According to MIT Technology Review, the experiment was just an exercise in science — the embryos were not allowed to develop for more than a few days and were never intended to be implanted into a womb. The publication first reported the news on Wednesday.
Officials at Oregon Health & Science University confirmed that the work took place there and said results would be published in a journal soon.
The scientists reportedly used a technique called CRISPR, which allows sections of DNA to be altered or replaced. The only previous work like this has been reported in China.