Children who spend long periods in daycare in their early years are likely to get on less well with their parents, be more aggressive and less well behaved;

Children most at risk of developing these behaviour patterns are those whose daycare began in their first year, was extensive (20-30 hours a week), and continuous until school age;

By "daycare" Prof Belsky means all care which is not provided by the mother; it is highly unusual for fathers or relations to provide that level of care over an extended period (at least in the US), and so their care can't be accurately compared with mothers' care;

The usual rejoinder that account has not been taken of the varying quality of childcare facilities is not valid; "dosage" is more significant than quality of care;

Though early, extensive and continuous daycare can be proved to present risks to children, no-one knows why this is the case;

So what's the solution? Prof Belsky advocates extended, and preferably paid, parental leave, tax policies favourable to stay-at-home parents. High-quality childcare facilities should also be provided by governments and their provision justified on humanitarian grounds alone