Boners.

They’re ubiquitous. Men get them, sometimes when they want, sometimes when they don’t. As a woman, you’d have to be living under a rock not to notice that boners often pop up at the most inopportune times. Like at the DMV. Or in church. Or when your coworker is in the middle of delivering a presentation to the rest of the team.

We all know that men get erections for absolutely no reason, especially when they’re younger but even when they’re older. For some, this can be a source of pride. For others, it can be a major embarrassment, both for the unfortunate fellow making excuses to hang back in his seat and for everyone else around him. But does random, occasionally unwelcome arousal happen in women? Is there a vaginal equivalent to an unsolicited stiffie?

 Like any good sociologist, I decided to do some exploratory research. Meaning, I asked a handful of my girlfriends.

Vittoria (not her real name), a bisexual Mexican-American mother in her mid-20s, was initially a bit reluctant to share her own experiences. Instead, she proceeded to tell me an embarrassing tale about her fiancé at the grocery store and the random boner he got in front of a bunch of families. But she finally admitted that she, too, had her own cringe-worthy story of unexpected sexual excitement.

It happened during a core cardio class at her local gym. During a side-ab exercise, Vittoria had an intense reaction, “probably because of the way my tight shorts were rubbing up on my clitoris.” No one noticed, but Vittoria said she was still mortified.

“I was at a place (the gym) where I should not be feeling the things I was feeling,” she said. “But the sensation kept intensifying into the subsequent reps, making me think all sorts of inappropriate thoughts. This was seriously getting in the way of my abdominal workout.”

Dr. Jordan Rullo, a certified sex therapist at the Mayo Clinic in Rochester, MN, said that sexual arousal for both men and women can fall into two different categories: psychological and physiological, which operate independent of one another.

There are times when women (and men) can be psychologically sexually aroused but their genitals are not displaying any signs of physiological arousal (e.g. vaginal lubrication, blood flow to the genitals, warm tingly feelings). And conversely—where your lady parts are aroused but your mind, not so much.

One big difference between women and men is the correlation between mind and body arousal. According to Dr. Rullo, that correlation is less than 30% in women. In other words, a woman’s mental arousal is not matching up with her physical arousal, or vice versa. The average correlation between mind and body arousal for men is more like 70%.

“Just like men, women can experience genital arousal even when they’re not psychologically sexually aroused,” Dr. Rullo said. “Women have nocturnal orgasms just like men. Also, just like men, women can experience genital arousal when their minds happens to wander to sexual thoughts, say during a really boring lecture.”

Amber (another pseudonym)—a mostly heterosexual woman in her late-40s who grew up in a pretty sexually repressive household—regaled me with tales of her “spontaneous orgasms” during sleep. “Sometimes it’s because of a sexual dream I’ve been having,” she said. “But a lot of times it’s not. I mean, not that I remember. And I don’t wake up rubbing on anything or touching myself. I just wake up in a full-blown orgasm.”

The experience is so awesome that Amber looks forward to it. “I go to bed thinking ‘I hope I have one of those dreams!’”

It would seem that ladies are just as randomly sexed-up as men. But it may go further than that. Despite what misanthropic cultural lore would have us believe, many researchers argue that women are more sexually responsive than men. According to Dr. Rullo, heterosexual women repeatedly demonstrate something called “non-gender specific sexual arousal.”

“Heterosexual women, when put in a research lab and instructed to watch erotica, will demonstrate genital sexual arousal to two men, two women, a man and a woman, and even monkeys (Bonobos) having sex,” she said.

“Further, women demonstrate genital sexual arousal to actors and images that they psychologically would not say they were sexually attracted to,” she continued. “Men, on the other hand, do not show this same pattern. Men demonstrate sexual arousal only to the actors and images that correspond with their psychological sexual arousal, and they are gender-specific.”

Long story short, women are sexually responsive to a much wider scope of stimuli than men, thus they have much greater opportunity for random arousal. Consequently, according to Dr. Rullo, women may experience more unwelcome genital sexual arousal than men.

So why, if it’s so common, is it also such a mystery? Guys love discussing and making jokes about their inappropriate boners. But for women, a vaginal stiffie is something that isn’t discussed or comes with too much personal shame.

Men love their erections and talking about their erections. (Try to tell me this isn’t true, I dare you.) But while women have random arousal comparable with (or even more frequent than) men, it’s not a subject that many women want to talk about or even attempt to explain.

The majority of women I interviewed for this story had to think long and hard about my questions. Not just about when they have unexpected proverbial boners, but why.

“It’s a bit unknown why some women can be writing a term paper or answering emails and suddenly get aroused,” Dr. Karen Kish, a private OB/Gyn practitioner in Austin, TX, told me. “The female sexual cascade is so convoluted and much more complicated than in men.”

Chauntelle Tibbals, Ph.D., is a sociologist living in Los Angeles, Calif. Visit her at chauntelletibbals.com or on Twitter at@drchauntelle