Preschool children in joint physical custody have fewer psychological symptoms than those who live mostly or only with one parent after a separation, according to new research from Sweden.

In a new study of 3,656 children between the ages of 3 and 5, researchers from Uppsala University, Karolinska Institutet, and the research institute CHESS found that kids living alternately with their parents after a separation show less behavioral problems and psychological symptoms than those living mostly or only with one of the parents.

The practice of joint physical custody — children living alternately and spending approximately the same amount of …