Those who defend Judge Brett Kavanaugh against allegations of sexual misconduct in high school and college point to his “immaculate” professional reputation and three decades as a loving husband and father as proof that he couldn’t possibly have assaulted Christine Blasey Ford and exposed himself to Deborah Ramirez, as the women claim.

“Kavanaugh may have been a rowdy, at times unruly, youth,” writes Washington Post columnist Kathleen Parker. “But barring future evidence to the contrary, this doesn’t make him a sexual predator.”

But the three-decade absence of any other sexual misconduct allegation is not proof that the Supreme Court nominee is innocent. And that line of defense betrays a fundamental misunderstanding about the types of men who commit acts of sexual aggression against others.

In fact, it is actually fairly common for sexual offenders to commit their crimes only in their teen or early adulthood years, said Kevin Swartout, an associate professor of psychology at Georgia State University.

“We have this group of guys who offend in high school, and if they offend in college, it’s within the first year or two of college,” said Swartout. “By the end of college, they just don’t offend anymore.”

HuffPost talked to Swartout about his research to learn more about this group. While Swartout was not saying that Kavanaugh was among this group of youthful sexual offenders, he did say that his research shows it’s possible for young men to assault women and then go on to never behave that way again.

Swartout studies the social factors that influence violence against women, as well as how alcohol use is linked to aggressive behavior. In general, he said, people who exhibit antisocial behaviors like sexual assault break down into two groups. Researchers call the first group “life course persistent,” which means that they perpetrate antisocial acts throughout their lives and may even turn into career criminals.

But there’s another type of antisocial behavior known as “adolescence limited.” These offenses are committed in teen and early adulthood years, but a mix of things like a changing social context, the full maturation of the brain and their entry into adult society lowers the risk of future antisocial behavior.

“Do they go on to be loving parents and loving husbands and model citizens? We don’t know that,” said Swartout. “But I would say that it does make sense that you’re not seeing the reports of sexual violence continue.”

When we think about sexual predators, the image that most often comes to mind is a small minority of men who rack up countless victims over the course of decades. This has held true in investigations into Catholic priests who get transferred from parish to parish and molest hundreds of children over the course of their lifetime, and the series of Me Too investigations inspired by the New York Times’ unmasking of Harvey Weinstein, who used his power and influence to rape women and then silence them by threatening their livelihoods.

But Swartout’s research reveals that most men who commit sexual assault in their teen and early adult years report only doing so within a limited time frame, and that the likelihood of committing rape changes as time goes on and the men transition from high school to college.

For instance, his 2015 survey found that many who commit a rape in high school don’t do it again once they’re in college. He also found that most men who commit rape in college did it once, complicating the mainstream narrative of the serial sexual predator.

Why is this? Why would a man rape a woman once but then never rape someone again?

The answer may have to do with the friends he has, how much he drinks and what his views are toward women, Swartout explained.

Risk factors for rape that are inherent in the individual have to do with that the popular press and social media refer to as “toxic masculinity.” This is a set of attitudes among some men that pit them against women because of the belief that all women are out to get them, that women are inherently untrustworthy and that all interactions with women are adversarial.

Swartout declined to speculate on the credibility of Kavanaugh or his accusers, including Blasey and Ramirez.

Context also matters, said Swartout, and the two biggest factors are heavy drinking and having a friend group that encourages violence against women.

“These guys aren’t wearing T-shirts that say, ‘Hey, I’m a sexually violent guy, and if you are, too, come hang out,’” Swartout explained. Instead, acceptance of sexual violence against women is more subtle, and it is hidden in a way of speaking to and about women as if they are objects that can be traded or shared.

“Comments that objectify women and take away individuality and choice” are key signs that a male friend group might be encouraging or accepting of sexual assault, said Swartout. Research on the influence of male peers on those who commit rape finds that sexual assault perpetrators feel more pressure from their friends to have sex by any means and that their friends make more objectifying statements about women compared with the friend groups of men who don’t commit sexual assault.

In Ford’s and Ramirez’s allegations against Kavanaugh, his friends ― and their shared laughter at the victim ― are prominent in their memories. Ford testified that the most salient memory she had of that day as a teen was the laughter that he shared with Mark Judge, and Ramirez said that a group of people were egging Kavanaugh on as he laughed and shoved his penis in front of her face.

Swartout’s research shows that diverse friend groups and tightly knit friendships lower the risk of both hostile attitudes toward women and sexual violence against women.

“If a young guy [who perpetrated sexual assault] goes off to college and makes friends with a peer network that isn’t supportive of sexual violence and doesn’t drink as much, that removes some of the risk factors,” he said.

Swartout points out that the majority of men who socialize in environments where there’s heavy drinking and opportunity to assault women don’t victimize anyone. He also noted that you don’t have to be a man to express hostility toward women.

But the acceptance of non-consensual sexual contact because “boys will be boys,” or the downplaying of assault as an inevitability that girls must put up with, all contribute to social factors that raise the risk of sexual assault. If contexts can change, so can behavior.