The purpose of the study was to show the effects of daycare, which it did.
So if both parents must work I suppose to most of the thinking here they are bad parents for leaving their children in daycare? I have seen many a family saved by the fact that both parents held jobs. When the husband lost his job his wife still had a salary that could pay the mortgage and put food on the table. The family kept on going while in a crisis, not as huge of a crisis if there was no cash coming into the home. Most women do not work because they want to, they must. So self righteous indignation at people who must work to give their children and families a better life is laughable.