For decades, psychologists and other researchers assumed that the mother-child bond was the most important one in a kid's life. They focused on studying those relationships, and however a child turned out, mom often got the credit — or blame.

Within the last several decades, though, scientists are increasingly realizing just how much dads matter. Just like women, fathers' bodies respond to parenthood, and their parenting style affects their kids just as much, and sometimes more, than mom's.

"We're now finding that not only are fathers influential, sometimes they have more influence on kids' development than moms," said Ronald Rohner, the director of the Center for the Study of Interpersonal Acceptance and Rejection at the University of Connecticut.

Feeling dad's love

Rohner and his colleagues recently reviewed decades of studies on parental acceptance and rejection across the globe. Unsurprisingly, parents have a major effect on their kids. When kids feel rejected or unloved by mom and dad, they're more likely to become hostile, aggressive and emotionally unstable. Parental rejection also can lead to low self-esteem, feelings of inadequacy and negative worldviews.

This is true for both parents, Rohner told LiveScience. But in some cases, dad is a more important factor than mom. [History's 12 Most Doting Dads]

Behavior problems, delinquency, depression, substance abuse and overall psychological adjustment are all more closely linked to dad's rejection than mom's, Rohner said.

By the same token, dad's love is sometimes a stronger influence for children than mom's, the researchers found.

"Knowing that kids feel loved by their father is a better predictor of young adults' sense of well-being, of happiness, of life satisfaction than knowing about the extent to which they feel loved by their mothers," Rohner said. He and his colleagues detailed their findings in May in the journal Personality and Social Psychology Review.

Influence and persistence

The research looked only at male father figures, so while the dad in question doesn't have to be biological, the results don't apply to absentee fathers. Rohner and his colleagues aren't certain why fathers sometimes outshine moms in their kids' development. In every family, Rohner said, there is a member with more influence and prestige — the person who might set the weekend plans, for example. In families where dad is that person, his actions might make the greatest impression on the children.

In those cases, "kids tend to pay more attention to what dad does and dad says than mom, and he's going to have more influence," Rohner said.

Dads may also be responsible for endowing their kids with "stick-with-it-ness" that serves them well in life. In a study of two-parent families published Friday (June 15) in the Journal of Early Adolescence, Brigham Young University researchers found that dad's parenting style is more closely linked to whether teens will exhibit persistence than mom's parenting. A persistent personality, in turn, was related to less delinquency and more engagement in school over time.

The magic fathering style that was linked to such persistence in kids is called authoritative parenting, a style characterized by warmth and love, accountability to the rules (but explanations of why those rules exist), and age-appropriate autonomy for kids, the researchers found.

"Our study suggests fathers who are most effective are those who listen to their children, have a close relationship, set appropriate rules, but also grant appropriate freedoms," study researcher Laura Padilla-Walker told LiveScience.

It's not clear why dads might be more important than moms in teaching perseverance, but it's possible that fathers simply focus on this trait more, while moms teach traits like gratitude and kindness, Padilla-Walker said. [5 Ways to Foster Self-Compassion in Your Child]

Being a good dad

Fortunately for dads, biology is there to back up good parenting. Hormonal studies have revealed that dads show increased levels of oxytocin during the first weeks of their babies' lives. This hormone, sometimes called the "love hormone," increases feelings of bonding among groups. Dads get oxytocin boosts by playing with their babies, according to a 2010 study published in the journal Biological Psychiatry.

Fatherhood also leads to declines in testosterone, the "macho" hormone associated with aggressive behavior, according to research published last year in the journal Proceedings of the National Academy of Sciences. This change is stronger the more involved a dad is with his baby's care, suggesting that it may reduce a man's risk-taking drive and encourage nurturing and domesticity.

What's most important, Padilla-Walker said, is that fathers realize they matter. Quality time is important, she said.

"That doesn't mean going on fancy vacations, it can be playing ball in the backyard or watching a movie with your kids," she said. "Whatever it is, just make yourself available and when you're with your children, be with them."

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