When mothers perceived fathers to be competent caregivers, the more time those dads spent solo with children, the lower was mom’s self-competence rating. But when mothers considered spouses relatively incompetent caregivers, increased father-only time with kids was unrelated to mothers’ self-competence.

As for why a mother’s self-competence took a hit from perfect dads, Sasaki suggests pressure to keep up with societal norms plays a role.

“In American society, women are expected to take a main role in parenting despite increasingly egalitarian sex roles,” Sasaki said. “Thus, we believe that employed mothers suffer from self-competence losses when their husbands are involved and skillful because those mothers may consider that it is a failure to fulfill cultural expectations.”