Why have scientists been slow to understand women’s sexuality

What do women want? It’s a question that’s stymied the likes of Sigmund Freud to Mel Gibson. It has been at the centre of numerous books, articles and blog posts, and no doubt the cause of countless agonised ponderings by men and women alike. But despite decades spent trying to crack this riddle, researchers have yet to land on a unified definition of female desire, let alone come close to fully understanding how it works.

Still, we’ve come a long way from past notions on the subject, which ran the gamut of women being insatiable, sex-hungry nymphomaniacs to having no desire at all. Now, scientists are increasingly beginning to realise that female desire cannot be summarised in terms of a single experience: it varies both between women and within individuals, and it spans a highly diverse spectrum of manifestations. As Beverly Whipple, a professor at Rutgers University, says: “Every woman wants something different.”

We’re also coming to realise that male and female desire might not be as dissimilar as we’ve typically assumed. For decades, researchers bought into society’s belief that men have higher desire than women, since large studies consistently confirmed that finding. But more recent evidence reveals that differences between the sexes may actually be more nuanced or even non-existent, depending on how you define and attempt to measure desire. Some studies have even found that men in relationships are as likely as women to be the member of the couple with the lower level of sexual desire.

Women don’t have lower sexuality than men. What they have are more variable patterns

Past studies typically asked participants things like, “Over the last month, how much desire have you experienced?” When that question is posed, men do typically rate higher than women. But when the question is revised to ask about in-the-moment feelings – the amount of desire experienced in the midst of a sexual interaction – scientists find no difference between men and women. “This challenges our gender-related stereotypes about women being passive and not sexual,” says Lori Brotto, a professor of obstetrics and gynaecology at the University of British Columbia, and a private practice psychologist. “It also suggests that the factors that elicit desire in the moment might be equally as potent for men as for women.”

Others have found that women’s desire waxes and wanes with their menstrual cycle. “During women’s peak period of arousal, which occurs around ovulation, their sexual motivation is just as strong as men,” says Lisa Diamond, a professor of psychology and gender studies at the University of Utah. “Women don’t have lower sexuality than men. What they have are more variable patterns.”

This makes sense when thinking in terms of sex’s ultimate purpose: making babies. “Biology, which helps to drive reproduction, is an element of sex,” says Anita Clayton, chair of the Department of Psychiatry and Neurobehavioral Sciences at the University of Virginia. “It’s only in modern times that reproduction and sex are uncoupled.”

Women do not necessarily experience the same progression of excitement, plateau, orgasm and resolution that men do

Previously, doctors had also assumed that the male sex hormone testosterone could be linked to female desire. In fact, it probably does not play a major role: several studies found no difference in testosterone levels in women who have high levels of desire and those diagnosed with a desire disorder. Despite this finding, women continue to request testosterone as a treatment for low desire, and doctors continue to prescribe it – often based on lab tests that erroneously use male levels of testosterone as a marker for what normal levels of that hormone should look like in a woman’s body.

Other research finds that testosterone and desire are linked only very indirectly, and that sexual activity has more of an effect on hormone levels than hormones do on whether someone actually desires sex. Sexual thoughts increase testosterone in women, as does sexual jealousy. “Thinking that sex just comes out of testosterone is such a falsehood,” says Sari van Anders, an associate professor of psychology and women’s studies at the University of Michigan, Ann Arbor, whose lab led the investigations. “Hormones have such small – if any – influence on desire.”

Even the variety of feelings during sex itself had gone unrecognised: women do not necessarily experience the same progression of excitement, plateau, orgasm and resolution that men do. Instead, the order is often shuffled. Sex itself can be the trigger for desire and arousal, or a first orgasm might lead to the desire for a second. “Often for women, genital, physical arousal precedes the psychological experience of desire,” Diamond says. “Whereas in men, desire precedes arousal.”

Desire, however, does not necessarily entail the wish to engage in sex with another person. Each woman (and, indeed, man) is different in terms of preferences, and those preferences may change at different times. Women may sometimes or always desire solitary masturbation, and some can even experience orgasm purely through thought, with no physical contact at all. Others may desire sexual activity with a partner, but without penetration or without ending in orgasm. “When people say they have a high desire for a partner, they might actually mean they want to be close to someone, or relieve their boredom, or experience something or someone new, or experience orgasm,” van Anders says. “My guess is that desire depends on the context, the person, the time of their life, relationship factors and who’s available.”

The range of turn-ons women report are extremely varied as well. Some prefer G-spot stimulation, or for their partner to suck on their toes. Others like to dominate, or simply to be held – the list goes on and on. “Usually clitoral stimulation is equated with males, but we’re documenting in the laboratory that women respond to a lot of other things, too,” says Whipple. “We need to educate women and give them permission to experience what they find pleasurable, and to let them know that they don’t have to fit into a single model of desire and sexual pleasure.”

That diversity is now reflected in porn – a relatively new development. Though women have always been involved in the industry, until the 1980s porn was largely geared toward a male audience. When home videos became available, however, porn – previously only shown in theatres – became more easily accessible to women as well as men. Picking up on this, female directors began creating porn marketed towards women, which often took a softer approach, with story lines lacking in violence, for instance. The industry has continued to evolve, however, with porn made by and consumed by women including erotic Victorian vampire sequences, all-male gay porn, monster porn and more. “It’s much more diverse now, because people realised that women are also perverts,” says Laura Helen Marks, a postdoctoral fellow in the Department of English at Tulane University. “Women have really taken up the camera and are responding to the diversity of female desire.”

Cultivating desire

At the most basic, neurological level, we still have no idea how desire works or what triggers it in the first place. “It’s not even clear what desire is, let alone how the activity of different parts of the brain combine to produce it,” says Barry Komisaruk, a distinguished professor of psychology at Rutgers University. “No one can do that reverse engineering yet.”

The reasons behind desire’s absence or loss, however, are often easier to pinpoint. Anyone who has ever been in a long-term relationship, male or female, will likely agree with the finding that desire is not static. Studies confirm that it tends to diminish in the context of long-term relationships. For women, however, the loss is often much more severe, possibly because testosterone provides a buffering effect for men against things like mood, stress and fatigue. Women, on the other hand, often feel that their relationship has lost thrill of the unknown and the sense of mystery and risk that they felt at the beginning, and that domestic life – including exhaustion, anxiety, stress and busyness – produce a smoldering effect. “A lot of women are working their asses off,” says Nan Wise, a certified sex therapist and research scientist at Rutgers University-Newark. “A loss of spontaneous sexual desire is not pathological – it just reflects many women feeling overloaded.”

Thankfully, however, desire’s departure in long term relationships is not a given, nor is it necessarily a permanent loss. It can be cultivated. Rekindling desire, Wise says, is sometimes as simple as introducing novelty into the relationship or life in general, which could mean traveling to a foreign country together, attending a sex party or learning a new skill. “If you and your partner are being dynamic in your life, then it’s as if you’re not having sex with the same person all the time,” she says. “When your partner does really cool new things, that’s a turn on.”

Sometimes lack of desire stems from overriding issues – a medical problem, a breakup, a job loss, the birth of a baby or any other stressful event. This is normal, however, and usually temporary. Large studies in the US and Britain have found that around 50% of women report periods of very low desire over the course of a year, but for many, it returns when they resolve the overarching problem affecting their life outside of the bedroom.

However, around 15% of women report a chronic lack of desire that causes distress. Many of them continue to have sex out of obligation, viewing it as another chore – albeit one that is dreaded. When sex actually takes place, those women may experience distracted thoughts, including benign but unsexy things about work or life, or judgmental ones, such as concern about their lack of response, worry about their appearance or anxiety about their partner leaving them.

A variety of solutions exist, though none work 100% of the time. Group, individual or couple’s therapy helps in some cases, while Brotto has found positive results with mindfulness meditation. Taking a cue from programmes meant to treat depression and anxiety, over the course of eight sessions, she and her colleagues debunk myths, educate participants about their bodies and bring awareness to various erogenous zones. They have found significant differences in groups of women who did and did not receive this training, as measured through self-reported questionnaires, endocrine activity and the women’s response to erotic films. Brotto and her colleagues are now performing another randomised control trial to try to identify the mechanisms by which mindfulness actually works, including whether the women are simply happier and less stressed or more aware of their bodies, or both.

‘Female viagra’ only increases the number of satisfying sexual encounters by 0.5 to one event per month

For now, most experts continue to recommend such treatments over pharmaceuticals, despite the fact that the so-called female Viagra, Addyi (flibanserin), gained US Food and Drug Administration approval last August. The comparison with Viagra, however, is less than accurate, as Viagra essentially solves a plumbing issue (blood flow to the penis), while Addyi affects the brain. But as Brotto points out, Addyi bases itself on a very narrow definition of desire – one due to an imbalance of serotonin and dopamine. That those hormones do not fully account for female desire is evident in the drug’s clinical trial results: Addyi only increases the number of satisfying sexual encounters by 0.5 to one event per month compared to the placebo. As van Anders says, “Imagine an allergy medicine that reduces a sneeze by once a month.”

Despite the low efficacy, the drug’s side effects – including dizziness, fatigue, nausea, insomnia, dry mouth, loss of consciousness and severely low blood pressure – occurred in about one in five women in the clinical trial. Those taking Addyi also cannot drink alcohol.

Diamond suggests that addressing the underlying psychological issues driving low desire may be a more effective treatment.

Not all women, however, are distressed by lack of desire. About 1% of the general population identifies as asexual – that is, they do not experience sexual desire for another person. Some assume that orientation throughout life, whereas others may go through phases of asexuality. “That’s a part of who they are, not a medical problem,” van Anders says. (Read our in-depth exploration of the Asexual Pride movement here.)

In other cases, distress over desire may be imposed by a partner who has higher levels and is making the other person in the relationship feel bad about it. “In general, women with lower levels of sexual desire do not see it as a problem until they get into a relationship where the partner has higher desire,” Clayton says.

But a boyfriend or husband who urges his partner to seek help or to change because her desire is less than his is inadvertently presuming that his higher level of desire is the “right” amount, Diamond says. “The issue is not low desire, it’s a desire discrepancy,” she says. “Rather than blame the woman, the better approach is to treat the couple and figure out how to negotiate the amount of sex that feels good for both people.”

If researchers know anything about desire, it is that variation is the norm. Whether male or female, desire can manifest in a seemingly endless spectrum of forms, and it can range from high to low to nonexistent. There is no right or wrong type or degree of desire for individuals or couples. “It would behoove us all to be more accepting of a very wide range of variability in desire,” Diamond says. “We need to be tolerant of diversity.”

—

This story is part of our Sexual Revolutions series on our evolving understanding of sex and gender.

Rachel Nuwer is a freelance journalist specialising in science, travel and adventure. Olivia Howitt is BBC Future’s picture editor. She Tweets as @OliviaHowitt.

Join 600,000+ Future fans by liking us on Facebook, or follow us on Twitter, Google+, LinkedIn and Instagram. If you liked this story, sign up for the weekly bbc.com features newsletter, called “If You Only Read 6 Things This Week”. A handpicked selection of stories from BBC Future, Earth, Culture, Capital, Travel and Autos, delivered to your inbox every Friday.