Moody Bitches: The Truth about the Drugs You’re Taking, the Sleep You’re Missing, the Sex You’re Not Having and What’s Really Making You Crazy.... Julie Holland

clingy clothing. They dress more fetchingly, wear more jewelry and perfume, and go out more when they’re midcycle and fertile. They’re also more likely to casually hook up, and less likely to use condoms. Women feel more attractive around ovulation, and men are able to tell which women are closer to ovulation and trying to look more attractive by examining their photos. In studies, men pay strippers who are ovulating more money than those who aren’t, and they rate the voices of women who are ovulating as sexier than the voices of those who aren’t.

      For that day or two when you have a viable egg, your body is being told by your hormones (especially testosterone) to go out and find a sperm donor. And not just any sperm donor. Our evolution dictates that we find the finest, fittest mate to donate his genetic material to our lineage. Introducing the alpha male—the best hunter, but not necessarily a good sharer. Women are also more likely to choose “bad boys” when they’re ovulating—the kind of guy with a five o’clock shadow and a motorcycle, who’d most likely arouse you but maybe won’t stick around and help you raise your kids. This dual sexuality is called conceptive and not conceptive. Some sex researchers call this dilemma “cad versus dad.” We want cads when we’re fertile, and dads when we’re not.

      In my office, the younger gals tend to go for men who excite and intrigue them, who have an edge and are hard to pin down. Women prefer men with a lower voice (more testosterone and likely more infidelity prone) for short-term mating but not for long-term relationship building. I’ve had countless heart-to-hearts with these patients about their choices in men. Often, as they mature, I remind them that the criteria need to change; they are shopping for a husband now, not a boyfriend.

      When women are ovulating, their mate selection focuses on masculine traits that signal good genetic material, the alpha-male DNA. When not fertile, women still seek out men, but are more attracted to “non-genetic material and assistance”—those with resources who’ll stick around to help with child rearing. Women, regardless of their own wealth, may still seek out men with adequate resources and social status. I know you have a job and a good credit rating and you don’t need a man for anything, but your brain is still more like a cavewoman’s than you’d like to admit. There have been no major changes to our genetics since we were hunter-gatherers. We’re naturally attracted to men who not only have money, power, and social rank but also have shown they will share it. Just not all month long.

      Women find classically masculine faces more attractive around the time they ovulate, choosing less chiseled-looking guys when not fertile. Fertile women are also more attracted to men acting in dominant, competitive ways. When we’re fertile, it’s all about genetic material, not social graces, which means if you’re in a relationship with a dad, you may still end up flirting with a cad midcycle. Like men, it’s natural for us to seek out the best genetic donor for our offspring. And also like men, even with a bird in the hand, we still go poking around the bush. Partnered women are more likely to choose the scent from a dominant man, while single women respond to the scent of men who are nurturing and willing to commit. It may be that even when a woman is partnered with a good provider (a dad), she can’t help but still be attracted to a man midcycle who could lend his exceptional genes to her next offspring (a cad).

      So what happens with women who are on oral contraceptives and never have a fertile phase? Just what you’d expect with static hormones. There’s no midcycle peak in oxytocin to push bonding and orgasms, and no surge in estrogen or testosterone stoking desire. As far as the brain is concerned, the deed is already done. If there’s a bun in the oven, there’s no need to attract a baker, and so the midcycle preference for the chiseled cad is gone. Women on the Pill act like women who are already pregnant, where the focus is to attract someone with other things to offer and share besides their manly genetic virtues. Pill users show weaker or no preferences for facial and vocal masculinity.

      The biological drives for food, drink, and sex ensure first our own survival and then the survival of our progeny. Clearly, women and men go about this differently, focusing on separate attributes we deem important. When searching for the best possible genetic donors, men follow their eyes and women follow their noses. Men are actually more likely to fall in love at first sight, and neuroimaging of men in the early stages of romantic love show increased brain activity in the visual centers. Men are swayed by facial symmetry, glowing skin, and a particular waist-to-hip ratio. These help to signal that a woman is healthy and able to bear children.

      When it comes to mating, women are influenced by scent. The sense of smell is the oldest and least mediated sense in our brains and processes information more quickly than the other sensory systems. Because the brain cells for smell are only one synapse away from the amygdala, our emotion center, we have no real control over liking or being repulsed by an odor. Women have a more sensitive sense of smell, and more brain space devoted to processing smells and pheromones, thanks to estrogen. Estrogen helps us to detect pheromones, the signature scent of a potential mate, more adroitly than men do, especially during ovulation, when estrogen levels are highest. For optimal mating, we need someone who’s in the Goldilocks zone of different but not too foreign: genetically similar and compatible, but not family. Pheromones from the male sweat glands allow us to make this determination. Women prefer the smell of a stranger’s armpit over that of family members, which is an ageless signal to prevent inbreeding.

      When it comes to mate selection, so much happens unconsciously that we don’t really have much control over. Pheremones are a good example. When a patient tells me she has a new boyfriend, I usually ask her if she likes the way he smells. I don’t mean his cologne or deodorant, and I definitely don’t mean his stink when he walks off the basketball court, but rather his scent, his natural odor. “If you stuck your nose in his armpit, would you be happy?” You’d be surprised how often this question is met with a resounding yes. When I hear “I could live there!” then I know they’re a good match. How someone smells to you matters tremendously. This is one of the reasons I’m not a huge fan of online dating. Pheromones help us to pick ideal mates for ourselves, and this process is based primarily on genetics, not on Photoshopped selfies.

      In 1995, Swiss researcher Claus Wedekind performed a study that has come to be known as the sweaty T-shirt experiment. He asked women to sniff T-shirts that men had been donning for three days without showering or using cologne. Wedekind found, and further research has confirmed, that most of the women were attracted to the scent of men whose major histocompatibility complex (MHC) was markedly different from their own. The MHC indicates a range of immunity to various disease-causing agents. When you’re mating, you want someone with different immunities than you have, so that your offspring can benefit from the variety. Optimally, children will have more disease-fighting capacity than either of their parents. Too-similar immune systems of potential parents can lead to complications in fertility and pregnancy. Also, if a woman partners with a man whose genetic makeup is too similar to hers, she’s more likely to cheat on him. The more genes they share, the more likely she’ll be attracted to other men.

      Pheromones are typically processed unconsciously, but lately this issue has come to the fore, and there have been more sweaty T-shirt parties going on around the country, a riff on the Wedekind experiment. Male invitees are told to bring a T-shirt they’ve worn for twenty-four hours (including overnight). They are assigned a number and the shirt is placed in a Ziploc bag. Women smell the shirts, choose the one