It makes a lot more sense if you think about WFH in terms of flexibility rather than being able to be home with your children all day every day. As you point out, the latter is unlikely to be super productive if you have young children. But at the other extreme, where the only option you have for work is being physically present in the office, any situation where it would be useful for a parent to be home requires taking paid time off. If they have a long commute, even scenarios involving partial days or just uncertainty around whether a parent needs to be home requires PTO where a WFH option might allow them to work for some or all of the day.
This also explains the results specifically impacting the number of children per mother. Having to take time off to deal with kid related things is much more manageable with fewer children, while even modest WFH flexibility might relieve that logistical burden even for much larger numbers of children. Just one or two days a week of WFH hybrid flexibility could take the place of 10-20 weeks of time off, which is far more than any employee is likely to have or need to deal with even the largest of families.
To preemptively address an obvious complaint about my comment, I'm not saying WFH replaces the need for taking PTO when it comes to childcare. Some childcare situations realistically would not allow the parent at home to work. But a lot of scenarios just require a physical presence or the ability to duck in and out with short notice. In those situations, having the WFH option is dramatically better than having to take the entire day off and removes one more burden of trying to work and parent at the same time.
This also explains the results specifically impacting the number of children per mother. Having to take time off to deal with kid related things is much more manageable with fewer children, while even modest WFH flexibility might relieve that logistical burden even for much larger numbers of children. Just one or two days a week of WFH hybrid flexibility could take the place of 10-20 weeks of time off, which is far more than any employee is likely to have or need to deal with even the largest of families.
To preemptively address an obvious complaint about my comment, I'm not saying WFH replaces the need for taking PTO when it comes to childcare. Some childcare situations realistically would not allow the parent at home to work. But a lot of scenarios just require a physical presence or the ability to duck in and out with short notice. In those situations, having the WFH option is dramatically better than having to take the entire day off and removes one more burden of trying to work and parent at the same time.