Does paternity leave lead dads to do more childcare?
Slightly more, even after they're back at work.
Taking leave during a baby's early months seems to encourage dads to do more childcare and housework long term.
For example, a 2006 reform that created five weeks of paid, non-transferable "daddy days" in Quebec led 80% of eligible dads to take leave, compared to 21% before the reform. That translated into about 2.2 extra hours of solo parenting per week over their child's first three years, as well as a lasting increase in dads' housework. Reforms that increased the uptake and duration of paternity leave in Sweden and Germany had similar effects, driving small but consistent increases in dads' caretaking and household labor shares after they returned to work.
Since paid paternity leave is so rare in the U.S., the American dads who take leave are a uniquely well-off, well-educated set who might be especially committed to egalitarian parenting. That makes it hard to estimate whether leave-taking changes dads' behavior in the U.S. context. That said, there's consistent evidence of a correlation between leave-taking and being a more involved dad over a child's early years.