Fisher-Price invented a popular baby sleeper without medical safety tests and kept selling it, even as babies died

Fisher-Price thought it had a hit on its hands.

It was 2009, and a small team of engineers at the toy company outside Buffalo seemed to have solved one of the most vexing problems for new parents: getting babies to sleep. Their invention was an inclined sleeper. They named it the Rock ‘n Play. It held babies on their backs in a padded frame at a 30-degree angle, like a recliner. There was nothing else like it. Cribs and bassinets laid flat. The difference was spelled out right on the box: “Baby can sleep at a comfortable incline all night long!”