They may not be talking about it, but more and more people are quietly grooming the hair around their private parts.

Fully 84 percent of American women have done something to their pubes in their lifetime, we recently learned.

But it’s not just women. Men are increasingly primping down there, too.

"It’s becoming more and more prevalent — and among men of all ages," Thomas Gaither, a medical student at the UCSF School of Medicine, told us. Gaither has authored or led many of the recent research papers on pubic hair grooming trends in America, including forthcoming studies on habits among males. "If there is anybody who knows things about men’s grooming, it’s me," he says.

Exactly why more men (and women) feel the need to remove some or all of their pubes isn’t entirely clear. For women, according to Gaither’s research, one of the leading drivers is a concern about hygiene. For men, it’s readiness for sex. "People point their fingers at porn" as helping to normalize or even encourage it, Gaither added.

What is becoming clear, however, is that all this primping and pruning is associated with an increased risk of injury and, potentially, disease.

Following a look at the health risks related to hair removal for women, I asked Gaither to outline what he knows about "manscaping." Our conversation follows, edited for length and clarity.

Julia Belluz: What do we know about how men’s pubic hair grooming habits have changed? And how do they compare with women's?

Tom Gaither: We know that 50 percent of men groom [their pubic hair] on a regular basis — that’s daily, weekly, or monthly. For women, it’s about 84 percent — much more common.

Most men are trimming, so not removing all of their hair. Women are much more likely to remove all their pubic hair when they groom.

But there is a select group of men who remove all their hair. If you look at men who have sex with men, they groom much more often than straight men, and they are much more likely to remove all their pubic hair.

JB: In one study about grooming injuries in men and women at ER departments, razors were the removal method most often associated with injury — by far. What kind of pubic hair removal do men use? And which is associated with injury?

TG: When men remove all their [pubic] hair, it’s usually with non-electric razors. And the next [most common method] would be electric razors.

Injuries are most often associated with an increased frequency of grooming. We thought it would be the opposite — that as you groom more, you’re an expert on your own body and get less and less likely to get injured. But people who groom more often are the ones who are getting injured.

"You don’t have this [as part of the] birds and bees talk from mom: 'This is how I shave my pubes'"

The most [common injury] is little lacerations. [For men,] scrotal injuries are very common, little nicks.

For men who have sex with men, we found that they are more likely to groom their anus and report injuries to the anus as well.

JB: So if grooming is becoming more and more common, and it’s associated with an injury risk, do you have any ideas about preventing injury here?

TG: Going forward, if we are going to prevent injuries we need to incorporate this stuff [information about safe grooming practices] in sex education for kids. It’s a taboo topic nobody talks about. In our surveys, people learned about pubic hair grooming from friends or something they saw on TV or porn. You don’t have this [as part of the] birds and bees talk from mom: "This is how I shave my pubes." But it’s going to happen regardless, and discussing safe ways [to groom] could make a big impact.

JB: For women, waxing pubic hair can pose a real danger, with burns, inflammation, infections, and skin tears. Do men wax, and is it dangerous for them?

TG: Men don’t [wax] as often as women. Some men do — but it’s less than 5 percent. On a regular basis, it’s less than 1 percent.

JB: You mentioned that men often groom for sex. Can you say more about that?

TG: A lot of people, and men in particular, groom for sex. That’s very well-known from what we’ve done research on. So if you groom before sex, you might disrupt your epithelial barrier [tissues, including the skin, that protect the body from damage], and you might be more susceptible to things transmitted via the epithelial barrier.

So that’s all the sexually transmitted infections that are cutaneous — HPV, genital warts, syphilis. We think there could be a relationship.

JB: So you are saying there’s a probable increased STI risk associated with grooming?

TG: The hypothesis is that if [shaving causes] small cuts, and you’re grooming before you have sex, and then you do have sex — you rub up on somebody else — that’s how diseases like HPV are transmitted. They are not transmitted through [ejaculations and other secretions] the way HIV or gonorrhea are. So we don’t think grooming puts you at higher risk for those diseases. But with HPV, genital warts, syphilis — we think there might be more of ... an increased risk associated with grooming.

JB: That’s sort of frightening; I had no idea that was a concern. Any advice on safe grooming for men?

TG: In one of our articles — on the influence of sexual orientation and role on male grooming-related injuries and infections — we found that men who used non-electric razors were much more likely to have infections and injuries, at least among gay men. We suggested that the use of electric razors might be safer and prevent infections.