Why do men send photos of their genitals?Here are some theories
(CNN) -- She's sitting in a crowded subway car, checking emails on her phone and minding her own business when it turns up: a photo of a man's penis.
Sexting is so common that 88% of male and female participants in a 2015 study said they had done it. So common that research psychologist Peggy Drexler wonders if there's any stigma attached to it. So common that, as we found out last week, even someone as prominent as Amazon founder Jeff Bezos said a news outlet was threatening to publish compromising photos of him.
READ: 1 in 4 young people say they have sexted, according to a study
If done in a consensual relationship, like other sexual behaviors, it is not necessarily harmful. But men often send women unsolicited photos.
There are several theories as to why.
Men often misperceive a woman's interest
Men are simply not good at gauging a woman's level of interest in him, says Alexandra Katehakis, founder and clinical director of the Center for Healthy Sex in Los Angeles.
"Yeah, they're bad at it," he told CNN. "And (photos) are not welcome."
Besides, says Katehakis, most women aren't interested in pictures of penises at all.
"They get more turned on by (images of) a man's eyes or his butt," she said.
Joe Kort, a sex and relationship therapist in Royal Oak, Michigan, has a point. "Most men really think that women would be willing and eager to see (an image of the penis) and that it would turn them on sexually. Of course, in most women this is not the case."
They're attached to their private parts
New York psychotherapist Jeannette Stern said this misperception is also due to men's attachment to their private parts.
"I think that men, generally more than women, feel a connection to their genitals and want the person they're sexually interested in to share that interest," Stern said. "I think men perceive this to be more pleasurable to the recipient than it often is."
They can get a thrill out of it
Some men are quick to share photos of their private parts with strangers, says Katehakis. Often they do this via what is known as a cyber flash.
Some men will use the iPhone's AirDrop feature to do this. AirDrop allows iPhone users to receive photos from people nearby if the feature is turned on and set to receive photos from everyone.
Some lawmakers in New York have proposed legislation to make it a crime, CNN affiliate WPIX reports.
It's just a high-tech version of male flashing from the past.
"It's not that different from old-school flashing," said Katehakis. "We thought of the creepy guy in the trench coat. This is the modern version of it."
In some cases, it's about hostility
Katehakis sees it as an act of rage against women, now leaked into cyberspace.
"For the male, it's very much about power and control. An act of sexualized hostility," he said. "Men take out their anger on women in erotic ways," she added.
The shocked reactions of the women who get these images are a big part of the emotion for the men who send them, said Kort, the sex therapist.
Can be related to dominance
Detroit sex therapist Russell Stambaugh explained that sending pictures of private parts is a combination of seeking acceptance and intimacy, bragging and seeking dominance.
"Given that bragging and seeking dominance are less conventional expressions in female gender roles, it's not surprising that men ... do this much more often," Stambaugh told CNN. "Because it is often an unsolicited pursuit of dominance, photos of men's genitalia are considered aggressive."
For many, it's somewhat impulsive
Many of the men lack impulse control, said Stern, the New York therapist. of drugs or alcohol.Someone who is more impulsive is more likely to send the photo, especially under the influence of these substances, whereas a less impulsive person might want to but think better of it.
"Thrill-seeking behavior like this with a partner feels safe, but cybercommunications really are never safe and seems like a lesson worth repeating," says Stern.
Is there some evolutionary basis for it
Are some men just programmed to do this sort of thing? Stambaugh is almost certain of that, saying that there is an evolutionary basis for some of the behavior of this type. He calls it "sexual signaling" which is designed to stimulate the conditions from which reproductive sexual behavior can occur.
Sex researcher Justin J. Lehmiller agrees with that sentiment, commenting on his blog about how something called error-handling theory works.
"One evolutionary theory suggests that males and females have evolved specific cognitive biases that may aid successful reproduction," Lehmiller writes. "From the point of view of this theory, the excessive perception of interest in sex, whether on Tinder or in the real world, could be considered adaptive, since it reduces the probability that men pass up any reproductive opportunity."
But Lehmiller adds that men shouldn't use that as an excuse for bad behavior.
"Even if we think this behavior is adaptive in an evolutionary sense, this doesn't make it okay or an excuse for men to send pictures to women who don't want to see them," she wrote.
After all, Katehakis said, we have evolved.
"It probably has some biological underpinnings," he said, "but we've evolved these big brains to reject all of that."
