Detailed discussions of diarrhea (Survivor). On-camera vomiting (The Bachelor, The Biggest Loser). Extensive cosmetic surgery (The Swan). Endless hot-tub makeout sessions (take your pick). On reality tv, no subject is too personal to reveal, no biological function too intimate to discuss—except for one final taboo too terrible to mention: menstruation.

Haven't you wondered what those women on Survivor do when they have their periods? The very premise of the show is that the cast ­members are thrown into the wilderness with nothing but the shirts (or bikinis) on their backs and one personal “luxury item.” Yet while all other bodily details, from rashes to dehydration, are examined in minute detail, not one woman ever talks about what it's like to live hundreds of miles from the nearest tampon dispenser.

On the archetypal dating show The Bachelor, all the rose-hungry ladies vying for the Bachelor's love live together. We see them applying makeup, confiding in each other about their dates, crying their hearts out to the camera, and occasionally vomiting after one too many wine spritzers. Last season, the ladies had late-night, alcohol-fueled discussions on such topics as sex with married men (moral of the story: nice girls don't!), sex with women (same moral), and their reactions to bachelor Jesse Palmer's admission of past one-night stands. They clashed and bonded, but they never asked each other, “Hey, do you have a tampon?” or commiserated over pms—despite the fact that, after weeks of living together, they were probably all on the same cycle.

Inquiring minds want to know how period protocol plays out on these shows. When I ask Christa Hastie, a contestant on Survivor: Pearl Islands, if the women had access to menstrual ­products, she exclaims, “That's the ­number-one question I had!” After noting that none of the former contestants had named tampons as their luxury item, she asked the pro­ducers: “Am I going to be the first person to have that as my lux­ury item?”

Jenna Morasca, the winner of Survivor: Ama­zon, says the topic was also foremost on her mind before the show. She then recalls of her eight-woman team: “Everybody except me started cycling at the same time. Everybody was crabby and bloated and hungry. It was like a slumber party gone terribly wrong.” Then Hastie gives me what they call, in reality parlance, the “reveal”: The women do have access to tampons, which are in a shared medical box (along with contact lenses and prescription medication).

Of all reality tv, one might assume that PBS's historical series detailing the hardships and challenges of life in days gone by, like Colon­ial House and Frontier House, would be the most likely to address the topic. But public television, much as it wants to educate us on other matters, shies away from details of old-time menstrual hygiene. (By contrast, the BBC's 1900 House, which was the inspiration for PBS's historical series, featured female inhabitants lamenting the work and discomfort involved in using cloth rags as sanitary napkins.) On PBS's 2004 offering, Colonial House, the producers even went so far as to zoom in on a bucket of urine and feces to show the inconvenience of emptying one's bowels in the 1600s. But although the show's women complained about not being able to take showers or wash their hair, they seemed conveniently menses-free.

In fact, I found out, some of them were: As on Survivor, a number of the women stopped having their periods altogether while filming, due to the extreme physical conditions and lack of food. But what about the others? At Plimoth Plantation, the Massa­chusetts museum that provided two weeks of training to Colonial House participants prior to filming, it was a subject of intense debate. “When the project started, we asked ourselves: How authentic do we get?” says Kathleen Curtin, a social historian at Plimoth. “The information on exactly what women did at the time is spotty, but we know that they ­didn't use tampons. One historian, who will remain nameless, suggested having the women use dry moss! That really bothered me—the par­ticipants on the show had bug spray, they had flashlights. To not give women tampons seemed too biased. Part of our job as historians is making sure that practices of the past don't cause health issues in the ­present. So we came up with a compromise [and gave them both] cloth rags and ­tampons.”

Why, I ask her, did this issue—clearly of interest behind the scenes—never arise on the show? “My guess is that they wanted to create a story arc,” she muses. “They filmed constantly and only used a minute amount of filming. They had a certain story they wanted to tell, and edited it down that way.” But, she adds: “Back in the 1600s, women were considered unclean when they were menstruating. Part of the reason we even have the information we have is because the terms used at that time for menstrual cloths and rags are synonymous with filth. And I think our culture has a similar kind of mentality.”

Survivor's Morasca makes the point that, due to the finite amount of airtime, not everything can appear on the program. But, she adds, there's more to it: “It's kind of like the taboo subject of the show. And it's a guy producer, so he's probably not willing to show certain things. If it were from a woman's perspective, it might be different.” You might think so—but the producers of Colonial House are all women. Colonist Amy-Kristina Herbert's observation puts the topic in a larger context: “The comparison I make is there were certain social behaviors that we engage in now that are contrary to the way the colonists engaged…. But it was interesting to see which issues people were willing to draw the line on and which ones they weren't. They wouldn't treat the [Native Americans] as the colonists would. But it wouldn't even cross their minds that it wasn't ok to be unfair to women. When you'd say, 'But that's sexist,' in response to something the men did, they'd answer, 'But that's how the colonists treated women, so I'm going to do it.' And I'd say, 'Then why don't you be racist?' But they wouldn't cross that line. So it tells me more about our society now than it does about the past.”

It's not like I expect menstruation to be the focus of these shows, or for Survivor to have a menstrua­tion-related challenge. But there's something really off when, in a media ­culture where no subject is ­unmen­tionable, the only thing that is is a biological function most adult, premenopausal women experience once a month; the omission is even more glaring on the shows that actually focus on physical hardships. And, as Herbert points out: “Not only were the producers of Colonial House women, three of the four directors were women, so it's mind-blowing that more women's issues weren't raised. I mean, if women won't do it, who will?”