Genetic prediction models are poised to revolutionize medicine. But because they have been trained on European DNA, they threaten to widen health care disparities.

The first tweets from the public appeared on July 15, 2006, several months after a soft launch. It was rebranded as X after being acquired by Elon Musk.

The babies were part of a vaccine trial for a respiratory virus in the 1960s and died shortly after. Their families said they had been unaware of the trial until recently.