Flickr / Geoffrey Froment As a young psychology intern in the late 1970s, my first patients were boys from divorced homes, suffering from what was then called “father hunger.” In those days, when parents split up, dads fell by the wayside. Fathers saw their children at the mothers’ discretion. This customary fallout from divorce reflected the belief that mothers are supremely important while fathers are expendable. We’ve come a long way since then.

Observing the problems that were being attributed to divorce, my colleagues and I began conducting studies in the late 1970s to learn how to help children cope better when their parents parted ways. The results of our research in Texas, supported by the National Institute for Mental Health, converged with studies in California, Virginia, and Arizona. The message from this work was clear: children and their fathers usually (though not always) wanted and needed more time together than they were getting. All signs pointed to the benefits for most families of having two parents involved in children’s lives who jointly maintained responsibility for their care. This is what is now called shared parenting.

Toward the end of the 20th century, divorce decrees offered children visits with their father every other weekend. The term visits captured the transformation of dad into something like an uncle, where the children are guests in his home. Dad became an entertainment director: The contacts were fun, but the texture and depth paled in comparison to a realistic parent-child relationship. At that time, only a handful of studies had peered into families in which divorced parents shared custody.

We now have more than 50 studies of joint physical custody. Using different methods, and examining families in the United States and abroad, the results are encouraging: children who spend at least 35 percent time with each parent, rather than live with one and visit the other, have better relationships with their fathers and mothers and do better academically, socially, and psychologically. As will be described next week at the International Conference on Shared Parenting in Boston, they get better grades; are less likely to smoke, get drunk, and use drugs; and are less susceptible to anxiety, depression, and stress-related illnesses.

Despite the obvious benefits of shared parenting, gender barriers don’t crumble easily and legal reform doesn’t usually happen without pushback. Although critics of shared parenting concede that children whose parents share physical custody enjoy many advantages, they reason that these children do better because their parents have more money and less conflict, not because their children spend nearly equal time with each parent. The critics also believe that if one parent opposes shared custody, it’s a bad plan for that family.

Linda Nielsen, a professor of educational and adolescent psychology at Wake Forest University, drilled into the research to test these ideas. She found that children whose parents share physical custody have better outcomes even when one parent initially opposed the arrangement and even when conflict between the parents was high. And the benefits of shared parenting were independent of the parents’ income. The lesson from her work? To ensure better outcomes for children of divorced parents, focus on improving the quality of their relationships with each parent by maximizing the time spent with each of them.

Most psychologists recognize the importance of keeping both parents actively involved in their children’s lives. But some draw the line when it comes to young children. Many people still think that moms should care for infants and toddlers and that we jeopardize children’s wellbeing if we trust dads with the job.

In practice, this means that young children whose parents split up spend every night in their mother’s home. Sleeping overnight at dad’s house is prohibited, even though the same child sleeps at day care, naps at dad’s house on Saturdays, and has sleepovers at grandma’s.

This blanket restriction continues even though dads push the baby stroller a lot more today than ever before in history. In dual-earner families, fathers account for 41 percent of the total time that both parents engage with their infants. This is good news for their children.

Fathers benefit from on-the-job experience just as mothers do. They learn to read their baby’s signals and respond sensitively. Fathers may even have a greater impact than mothers in some areas such as language development and persistence in facing challenging obstacles — the “can do” attitude that is essential to success.

To assess where science stands on the issue of shared parenting and overnights for young children, I spent two years reviewing the relevant scientific literature and vetting my analyses with an international group of experts. This work, published in an American Psychological Association journal, was endorsed by 110 leading researchers and practitioners.

Here are the two main conclusions: First, shared parenting should be the norm not just for children whose parents live together, and not just for older children, but also for children of all ages whose parents live apart from each other. Children need a father, not an uncle-daddy. Second, if we want to give children the best chance for normal relationships with their fathers, limiting fathering time to daytime hours until children enter kindergarten is not the way to do that.

To be sure, shared parenting is not for all families after divorce. But there’s a general consensus that it is good for many of them.

If we value dad soothing his fretful baby at 3 a.m. or reading “Goodnight Moon” to his toddler while the parents are living together, why deprive the child of these expressions of fatherly love just because the parents no longer live together, or just because the sun has set?

Richard A. Warshak, PhD, is a clinical professor of psychiatry at the University of Texas Southwestern Medical Center at Dallas. He's the author of “Social Science and Parenting Plans for Young Children: A Consensus Report” and “Divorce Poison: How To Protect Your Family From Bad-mouthing and Brainwashing.”