In the course of researching boys’ friendships over two decades, Niobi Way stumbled upon a link that appears, at first blush, to go against everything we believe about fatherly influence.

“The quantitative data from studying hundreds of boys show that high-quality relationships with their moms predict high-quality relationships with their friends,” says Way, a professor at New York University and the author of Deep Secrets: Boys’ Friendships and the Crisis of Connection (Harvard University Press).

“But the opposite is true with dads. The more time they’re spending with dad, the less they report having high-quality friendships.”

The finding gave Way and her fellow researchers pause, but it actually speaks to the heart of her thesis, which is, in essence: Boys want close friendships. Boys are equipped to foster close friendships. Boys, in fact, rock at close friendships.

Until they approach adulthood.

Way interviewed hundreds of boys — black, white, Latino, Asian-American — throughout adolescence, and found that they’re quite clear about the esteem with which they regard their friendships.

“I heard these 13-, 14-, 15-year-old boys saying, ‘I need my friends. I want close friends. I would go wacko without my close friends,’” she says. “Around 15, 16, 17, you start to hear a very different boy talking.”

Boys face a crisis in their relational abilities, say experts in the area of adolescent psychology. And the stakes are high. Way’s research links healthy, intimate friendships among boys with lower rates of bullying, better physical health, longer life spans, less drug and alcohol abuse and better academic performance.

The time at which most boys start to drift away from their close friends — typically age 15 or 16 — corresponds precisely with the time at which suicide rates for boys jump to five times the rate of girls, Way says.

“The question isn’t how do we teach our boys to have relationships. It’s how do we teach them to hang on to them,” Way says.

“How men relate to their sons often reinforces hypermasculinity,” the researcher says. “Closeness with their sons often entails going to sports events and talking about sports, which is fantastic. But it doesn’t necessarily entail emotional connectedness, talking about their emotional lives, which is why it’s affecting their friendships.

“That’s what we do to our boys,” she says. “We force them to be not quite human, quite frankly, by suppressing their emotions.”

Fathers — along with mothers, teachers, all of us, frankly — have a responsibility to foster and encourage connectedness and emotional honesty in our boys.

“You can’t have friendship without vulnerability,” says child psychologist Michael Thompson, co-author of Raising Cain: Protecting the Emotional Life of Boys (Ballantine). “You have to be able to let your guard down with somebody, and you have to be able to trust that somebody is going to look after you.”

Thompson makes a plea to dads: Model friendship for your sons.

“Take your sons and your sons’ friends with you on camping trips with your own friends,” he says. “Talk with them about why you like your buddies with a little more depth than, ‘He’s so funny.’ ‘He and I both like the Giants.’ ”

Chances are, the chats will be well-received.

“Boys are crying out for male attention in our culture,” says Lisa Bloom, author of Swagger: 10 Urgent Rules for Raising Boys in an Era of Failing Schools, Mass Joblessness and Thug Culture (Think Publications/Vantage Point). “Fathers and other men who want to play a role in kids’ lives have a wonderful opportunity to do so.”

And the benefits are large and lifelong. Better friends, after all, make better brothers, fathers, partners.

“Any relationship that is mutual and reciprocal and loving,” Thompson says, “gives you practice for other relationships that are mutual, reciprocal and loving.”