Sometimes science delves into taboo subjects — and turns up interesting results. This year was no exception, with researchers delving into such blush-worthy topics as premature orgasms, sex toys and even bestiality. Here are 10 of the stories that reddened our cheeks in 2011.

1. Premature orgasm isn't just for men

It's not just men who struggle with finishing too early in the sack. According to research published in the journal Sexologies in October, premature orgasm may be more common than expected in women. In a preliminary survey of Portuguese women, researchers at the Hospital Magalhães Lemos in Porto, Portugal, found that 14 percent had frequent and distressing early orgasms during sex. The women couldn't control their orgasms and often found that they were uncomfortable continuing with sex afterwards, leaving their partners in the lurch. According to the researchers, more research is needed to find out if female premature orgasm, like male premature ejaculation, should be an official sexual dysfunction.

2. Americans love vibrators

 This may or may not come as a surprise, but Americans are apparently quite approving of sex toys, at least for women. A national survey this year found that about half of respondents agreed with statements such as "a vibrator is a healthy part of many women's sex lives." In comparison, fewer than 10 percent of respondents agreed with negative views, including the belief that vibrators are intimidating to a woman's partner.

An earlier analysis by the same researchers found that 53 percent of women and 45 percent of men had used vibrators in their lifetimes. Furthermore, vibrator use was correlated with sexual satisfaction.

3. Meditation can be sexy

Another way women can get more out of sex: meditation. According to research released in November, women trained in "mindfulness meditation" became more aware of their bodies' responses to sexy stimuli such as erotic photographs. This meditation, which teaches people to stay in the present, seems to silence the chatter of anxious and insecure thoughts that plague some women during sex, the researchers reported in the journal Psychosomatic Medicine. We'll never look at a yoga class the same way again.

4. Early humans were sexual experimenters

The news that humans and Neanderthals probably got busy with one another first broke in 2010. But 2011 has brought a succession of new research to enlighten us on just how friendly our early hominid ancestors got. In July, for example, researchers reported new DNA evidence that a particular Neanderthal gene fragment is present in 9 percent of humans across the globe, except in Africa. That means that the sexual tryst or trysts that led to this gene mixing would have happened soon after humans began to migrate out of Africa.

And in Asia between 23,000-and-45,000-years ago, humans got cozy with Denisovans, a mysterious human ancestor that forked off from the Neanderthal branch of the family tree.

On the other hand, all this cross-species intimacy may have been its own birth control. Research released in September found that human-Neanderthal interbreeding likely only led to offspring less than 2 percent of the time.

5. Teens think oral sex is less risky

Despite growing evidence that oral sex increases the risk of some head and neck cancers, teens think of it as a less-risky sex act than vaginal or anal intercourse, according to research presented in February at the annual meeting of the American Association for the Advancement of Science. Close to 14 percent of teens surveyed said they didn't think oral sex came with any health risks. In fact, because of the transmission of the human papilloma virus (HPV), having more oral-sex partners is associated with higher risks of mouth and throat cancers.

6. Vaccines don't cause teen sex

On the subject of teen sex, it turns out that vaccinating adolescents for HPV won't encourage them to dive into promiscuity. In research released this December and to appear in the January issue of the American Journal of Preventative Medicine, the Centers for Disease Control and Statistics reported that teen women who get the HPV vaccine are no more likely to engage in risky sexual behavior than unvaccinated women. 

In fact, girls who had the HPV vaccine were actually more likely to use condoms when they had sex than girls who didn't, likely because they were more knowledgeable about sexually transmitted diseases, the researchers reported. Apparently, the HPV vaccine is one thing we don't need to blush about.

7. College students: More talk than action

In September, researchers uncovered a truth that might deflate the egos of college students a little bit. Although students believe that casual sex, or hook-ups, are common on campus, there's a lot more talk than action going on in dorm rooms.

Researchers at the University of Nebraska-Lincoln queried students on how often they and their peers hooked up with other students. They found that perceptions rarely matched reality. For example, 90 percent of students thought that at-least-two hookups were "typical" for a college career. In fact, only 37 percent of people had that many. Inflating the number of notches on your bedpost never gets old, it seems.

8. Squid swim around covered in sperm

Animals generally are less uptight about sex than humans, rarely demanding trivial comforts like, say, privacy. But the deep-sea squid Octopoteuthis deletron takes casual sex to a new level. These squid live in the dark waters off the coast of California, and they rarely run into other squid of their species. When they do, researchers reported in the journal Biology Letters, the squid don't take the time to find out whether they've met a male or a female: They just ejaculate sperm packets onto their new acquaintance and jet out of there. Embarrassingly for the targeted squid, but useful for researchers trying to track mating attempts, the sperm packets stay stuck to the squid's bodies, signaling a recent amorous run-in.

9. There's poop on the coffee table

To veer away from sex for just a moment: 2011 brought us some very, very bad news about single men's coffee tables. According to microbiology researchers, bachelor pads harbor 15 times the amount of bacteria as the homes of bachelorettes. And some of those bacteria are the ones found in feces.

In fact, those fecal coliforms showed up on seven-out-of-every-10 coffee tables in single-guy homes sampled by researchers. The culprit is likely men putting their feet up on the table while wearing shoes, the researchers reported.

Single women shouldn't get too smug: fecal coliforms show up in their homes, too, just in lower concentrations than in the homes of single men. Other fecal coliform hot spots include the TV remote, nightstands and doorknobs.

10. Bestiality and penile cancer

If you took the first nine entries in this countdown in stride, prepare to cringe at least a little at number 10: According to research published in November in the Journal of Sexual Medicine, having sex with animals is linked with penile cancer.

Researchers managed to uncover this connection by studying 492 men from rural Brazil. They found that a whopping 35 percent reported sex with animals in their lifetimes. Men with penile cancer were more likely to have had sex with animals, the researchers found. They speculate that penile injuries plus foreign secretion from distantly related species may introduce microorganisms that cause cancer, much as the human papilloma virus does. Now if you'll excuse us, we're off to bleach our brains!

• 11 Biggest Science Stories of 2011
• Top 10 Wacky Animal Stories of 2011
• 10 Surprising Sex Statistics

Twentieth Century Fox

Meg Ryan showed millions of women how to convincingly fake it in an iconic scene from "When Harry Met Sally."

Half of you ladies have faked an orgasm at least once, scientists claim. Maybe you knew the real thing just wasn’t gonna happen, so you wanted to wrap it up and go to sleep. Perhaps you didn’t want to bruise his ego.

Or maybe you thought it was a way to keep your man from straying.

At least that’s what a new study concludes.

“By having an orgasm, women are signaling to their male partner that ‘I’m selecting you,’” lead author Farnaz Kaighobadi says.

Kaighobadi, a research fellow at Columbia University, and her coauthors wanted to see whether women would be more likely to send that signal, even if they weren’t really feeling it at the moment, if they suspected their mate of infidelity.

For their study, Kaighobadi and her coauthors recruited 453 straight women who’d been in a relationship for at least six months. The young women – 22, on average – all lived in south Florida. They were asked if they thought their partner would cheat if given a chance and if they’ve done so-called “mate retention acts,” like call their man at unexpected times to see if he was really home alone watching ESPN or held his hand when other women were checking him out.

As researchers suspected, women who thought their men were more likely to be cheating louts were more likely to stake their claim – and fake an orgasm.

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After six years of marriage, Ashton Kutcher and Demi Moore are splitting after rumors of infidelity. Here, they are shown at the launch party for

Demi and Ashton (you don’t really need their last names, do you?) have called it quits. Or, rather, Demi has called it quits, apparently, following rumors of Ashton’s moments with a-woman-not-Demi while visiting San Diego.

I write that not because you necessarily care about Ashton and Demi – though a lot of people seem to – but because it brings up the issue of monogamy and if we humans are truly built for it.

The full answer, as you might expect, is pretty complicated. I am currently writing a book with Emory University neuroscientist Larry Young, one of the world’s leading experts in pair bonding -- the way biologists talk about “love” and monogamy in animals -- that attempts to lay it out. But the short answer depends on two things: First, what do we mean when we say monogamy? Second, what’s going on in our brains?

According to Young, only about 3 to 5 percent of mammals form pair bonds between males and females. But even among those that do, “monogamy” does not necessarily mean sexual exclusivity. It means the partners share a social glue, raise a family together and comfort and defend each other. They might very well have sex with the neighbor critter down the block, though.

"Whether humans are monogamous by nature is debatable, and a matter of semantics," Young said.

Monogamy resides in the brain. Young studies voles, small, furry critters found all over North America. One species, prairie voles, is generally monogamous. Another species, the meadow vole, is not. These two species look virtually identical, and even when you look at their genes, there’s barely any difference. But subtle variations in parts of key, brain-related, genes make one monogamous and one promiscuous.

Even within prairie voles, there’s variation. Some are faithful, some play the field. Mounting evidence suggests this is true for people, too.

We know there are differences between human genders, too, with men reporting higher rates of infidelity than women (though women have been slowly catching up). There are several reasons why this might be so, but one is fundamental: Men, especially younger men, have evolved to be readily turned on. Female libido can vary significantly by cycle day.   

We don’t like to think that something we regard as so basic depends on a couple of molecules in our heads, the action of which can be determined by how we develop in our mothers’ wombs, or certain life events, but such forces do act on our brains, making us more or less likely to have extra-monogamy sex.

It’s not, as Demi suggested in her press statement, just a question of “values” or “vows.” How monogamy plays out for each of us also has a lot to do with how we are wired.     

Would cheating be a deal-breaker for you in your relationship? Tell us on Facebook.

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The fertility rate is dropping, statistics say. People are simply having fewer children. Experts think the reason can be traced to financial planning by would-be parents wary of their futures.

But is that really the case? Do couples really behave this rationally? A large percentage of all pregnancies are unplanned, so isn’t it also possible that stress, anxiety, boredom, and damaged relationships brought on by economic gloom and doom are simply killing the national sex life?

While some couples no doubt do plan carefully, and opt to delay having children until sunnier days arrive, says psychologist, therapist and TODAY contributor Gail Saltz, people are also preoccupied with money worries. She senses that many more people are experiencing anxiety and stress, and possibly depression, because of the economic pressure of the past four years.  

“And when people are worried, they don’t feel like having sex,” she explained. “This is especially true for women. It is darn near impossible for a woman to have an orgasm if she is terribly anxious. A woman can physically have sex, but desire, arousal, orgasm, everything across the board is affected.”

Picture the couple who’s scrimping and saving to make ends meet. They’ve cut out restaurant dinners, movie tickets, vacations, theater-going. They’re sitting in front of the TV in sweatpants watching another episode of “NCIS” or “30 Rock.” They look at each other think, "My God, the last thing I want to do is have sex with this person."

“If you can’t spend any money doing anything fun, if that’s sucked out of the relationship, too, you’ve got no novelty, no playtime,” Saltz explained. Both are critical to stoking libido.   

Finally, there’s the inevitable sniping between partners. “Money is the number one thing people fight about,” Saltz said, “but you don’t even have to disagree about it. If you are anxious or one partner is depressed, well, that’s the person you are intimate with and so it gets taken out on you. You have to negotiate it all, and then, no, you don’t really feel like having sex.”

So it’s probably not only considered financial planning that’s responsible for the drop in birth rates – a drop that also occurred during the Great Depression, by the way. Maybe it’s that America is stressed out, bored, and more than a little cranky. 

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If you were taking contraceptive pills when you met your husband, you may have a happier marriage. But your sex life might be meh.

Ladies, if you feel your partner is a great provider -- but meh in the love-making department -- it may have something to do with your birth control.

Women who were taking contraceptive pills when they met their significant other were more likely to stay in the relationship than women who weren’t on the Pill, according to new research. While the partners of the non-Pill taking women tend to be more handsome and better in the sack, their relationships just didn’t have the same staying power.

Good-looking and sexy or dull and nice. Seems there's always a trade-off when it comes to love.

The study was posted online Wednesday by the Proceedings of the Royal Society B.

Scottish and Czech scientists asked 2,500 women who were the biological mothers of at least one child about the father of the child and their relationship with him (not all the couples were married). And they also asked about the birth control they used when they met. The women were told only that the study was about their experiences of pregnancy and children and their relationship satisfaction.

Previous research has shown that hormonal variations over the menstrual cycle affect how women size up men as mate material. For example, studies have shown that women prefer more masculine men during ovulation than at other times of the month -- because the more macho, the more successful he is as a breeder.

Because the Pill smooths out those hormonal variations, researchers suspected that a muscle-bound hunk might not turn users' heads as much as a nice, average-looking guy with a steady job. And that's pretty much what they found. Women who'd been taking contraceptive pills when they met their partner were more likely to still be in the relationship. And while they rated their partner's body lower in attractiveness than women who hadn't been on the pill, they rated his "financial provision" more favorably.

"Our results show some positive and negative consequences of using the pill when a woman meets her partner," psychologist Craig Roberts of the University of Stirling in Scotland, said in a statement.

Other research by Roberts has found that oral contraceptives can also alter women’s preferences for men’s body odor. On the Pill, they gravitate toward the odor of men who are more genetically similar to them. But off the pill, they’re attracted to the odor of genetically dissimilar men when they’re ovulating.

“Women tend to find genetically dissimilar men attractive because resulting babies will be more likely to be healthy,” Roberts said in the release. “It’s part of the subconscious ‘chemistry’ of attraction between men and women.”

Because contraceptive pills smooth out those monthly hormonal variations, Roberts and his coauthors suspected Brad Pitt might not turn users’ heads as much as a nice, so-so-looking guy with a steady job. And that, pretty much, is what they found.