At Facebook, parents can take up to four months of paid time off to take care of their newborn child. But nationwide, nearly a third of men say taking leave -- paid or not -- is not an option. Many men report they are reluctant to take time off, even if offered, for fear it will hurt their careers. Researchers found that dads who reduced their hours or went to flexible schedules for family reasons got lower raises and received poorer scores on evaluations. We discuss the decision to take paternity leave.