Most chapters in this book deal with subjects that are the domain of professionals. Sex is best left to amateurs, a statement not so easy to make about the treatment of cardiovascular risk.
It’s a relief to find how little medicine has to say about human sexuality. This chapter should describe patterns in human sexual behaviour and consider variations and patterns of it geographically and historically. That information, happily, is not available. For all that Kinsey and others have taken snapshots, there exists no epidemiology of sexuality, no reliable chart of prevalence and incidence. From pregnancy and disease and other sources we can make inferences but there is not much to them. Sexual activity, for example, plainly starts for many at below the age when the law says it should. Rates of coital frequency can be estimated,1 which should provide fun material for journalism but can only be a distraction when it comes to matters we really wish to think about. ‘My marriage was like the marriage of other people’, wrote Trollope in his autobiography, ‘and of no special interest to any one except my wife and me.’2
The interest we find in our own sexual lives is not easily augmented by peering into those of others. Prying has a habit of seeing everything through the distorting lenses of prurience; adolescents telling each other about their early sexual experiences are unlikely to be telling the truth, and even when they try their efforts will most likely be distorted by having an audience. Being grown up does not involve discovering what everyone else is up to so much as accepting that it’s none of your business. Voyeurism is not an aid to happiness or good sense.
There is precious little to report of genuine value about the sex lives of our fellows – at least not directly. There is a reason why art works by hints, and pornography is not art. When Justice Potter Stewart of the US Supreme Court famously defined pornography – ‘I know it when I see it’ – he left open the suggestion that here, too, the eye of the beholder mattered. The converse of prying being bad is that intimacy depends on privacy. The lack of information about human sexual activity, in contrast to the wealth of data we have about other aspects of people’s lives, is heartening.
The name links them to Aphrodite, Greek goddess of love, but aphrodisiacs pre-date her and pre-date the Sumerian goddess Inanna on whom she was modelled. Gauging the future of aphrodisiacs in human lives involves taking the measure of our past relations with them.
In the oldest existing medical text, erectile dysfunction is fought with henbane, animal brains, beans, dirt, sawdust of pine and willow and juniper and sycamore, acacia juice, flaxseed, onion, oil, goose fat, pig’s dung, myrrh, salt and ox fat. Bandaged together to the wilting penis they brought it new life.
If an ancient physician declared a problem treatable, yet failed to treat it, there were consequences. The Sumerian legal code of Hammurabi stated such doctors might not get paid. In some circumstances injury was added to insult and the injury took the form of them having their hands cut off.3 This had the power of concentrating the medical mind wonderfully. Where there was little or no chance of success, the correct action was to declare that a problem was not treatable and to refuse to try. The ancient wisdom and natural ingredients the Ebers papyrus lists must have worked. If they hadn’t, the prescription – and perhaps the physician – would not have survived.
For those unable to afford the mix of ingredients listed in the papyrus, and the physician to bandage them onto the disappointing penis, another treatment was available. It was simpler but, as the Greeks warned, it could cause so powerful an aphrodisiacal frenzy that it needed to be used with care.4 The aphrodisiac in question was lettuce.5 Romaine, in fact, which for those unfamiliar with their salad varieties is not a round lettuce but a proud upright one. To Egyptian eyes it looked phallic. That, and the fact it oozed an opaque milky-white sap when cut, formed the mental link.
Those who could afford it went for the mixed ingredients of the penis poultice. If the contents of that should by any chance not seem varied enough, the history of aphrodisiacs contains more, many more. Many are exotic while others, like lettuce, have lost the exoticism they once possessed. Soon after its introduction to Europe, it was widely understood that an ageing libido could be restored by a rare and special tuber from unimaginably distant shores. Hence the greedy invocation of Falstaff, the old goat, to ‘let the sky rain potatoes’.6
Only one explanation accounts for so many different agents working, and then, as cultures change, ceasing to work and being replaced. Of all the vast array of aphrodisiacs with which people have draped, dosed and sprayed themselves, none has the slightest actual effect.7 None work, that is, in the manner in which people have believed them to, through some pharmacological effect. There’s an opportunity missed every time one shucks an oyster in the belief it contains some special chemical, not least when a seduction might fail if the target of one’s lust prefers parmesan to molluscs. The message is more than that we fool ourselves when it comes to sex, or that the flux of human variation makes it impossible to spot a placebo from an effective drug without structured experiments. The message is that we are strongly attracted to false biological explanations for traits of character and culture.
The insertion of slices of chimp testicle into older men, to restore their libido, ‘can be looked upon as the Viagra of the 1920s’8 said one historical review – a useful comparison to bear in mind when we jump forward and consider the Viagra of the modern era… Viagra. The little blue pill is not a lot to look at but its cultural impact has been huge. When we consider its actual pharmacological effects, could there be less than meets the eye? Developed in the hope of dilating blood vessels, and thus being an effective treatment for high blood pressure and the angina caused by narrowed coronary arteries, Viagra went through the normal process of investigation for a promising drug. Early on it was given to a small number of healthy volunteers, an experiment designed not to test its effectiveness but to ensure its safety and check for unexpected side effects.
A number of these healthy young men, the experiment revealed, did indeed experience some side effects. The drug gave a minority of them an erection.9 That led to a different kind of excitement for drug company Pfizer, in the form of sales of billions, and prompted the manufacture of similar agents that work via the same molecular route but stay in the blood for longer, meaning sexual spontaneity could be unplanned. It also helped reinforce our powerful belief in the idea of performance-enhancing drugs. Recreational use of Viagra and similar drugs is common. It is hard to know how common, since it is illicit, but a Brazilian study found that 9 per cent of healthy young Brazilian men had used them10 and in Argentina the figure was 22 per cent.11
When given to healthy young men, Viagra makes erections easier to obtain, firmer and longer lasting. It confers more intense orgasms and reduces the refractory time following them, accelerating recovery. Super stuff and not necessarily a trivial boon to human life. But placebos, in the same trial, did all those things too.*12 Viagra can have an effect on physical problems but its effect on psychology is greater, both when there is no problem to begin with and also when there is. ‘It achieves success rates of up to 80 per cent in patients with organically caused dysfunction, and more in patients with predominantly psychologically caused disturbances.’13 Striking that the drug should be even more effective when used in those with no physical problems. Why should this be? And why should it be that Viagra’s erection-causing effects in healthy men were picked up accidentally in a study that wasn’t looking for them, but are absent in other studies set up precisely to investigate them? Could it be that Viagra’s effectiveness is a mirage, and that its biochemical power is no more than is to be expected of someone swallowing a salad – dressed with sufficient expectation of effect – of lettuce and potato?
The widespread use of Viagra by healthy young men is certainly testament to the preoccupations of young men and the power of placebos. Pharmacological aphrodisiacs, including Viagra for those in good sexual health, do not generally work.14 That is, drugs to enhance and improve upon normal human sexual function are figments of our imagination. Drugs can certainly alter human sexual function, and improve it in some ways at the expense of others, but none acts to simply improve it and none ever will, since our sexuality is not itself the simple product of any single biochemical pathway, and that’s all a drug can change. Those drugs whose aphrodisiac impact is real work in the same way as all the other effective aphrodisiacs, from longing to love: they work on the mind. Alcohol is the most common. ‘Studies examining the effect of alcohol on female sexual function are very limited with inconclusive results’15 is a statement that finishes well but starts badly. To suggest few such studies have been done is to ignore a vast body of informal work on the subject. Mind-altering drugs like gin modulate our experiences in the same way as love, empathy, imagination and food, drink, clothes and music. The idea that drugs are out there, in our pharmacies or in our futures, to turn us into sexual superheroes, is not a new one nor one that will ever get old. In the future we will continue to believe in such things and continue to be fooled by them. We shall not find them because they cannot exist, not in the way we imagine them. The idea of them rests on a simplified conception in which psychological traits possess a one-to-one correspondence with a biological switch or state.
Does Viagra actually work at all? The accumulated evidence says it does. Such reviews can be flawed. Viagra and similar drugs cause side effects; in a placebo-controlled trial if someone taking the pill notices the side effects, even unconsciously, they will have some realisation they are not on the placebo. If they can tell the difference, the trial isn’t testing the difference between the drug and a placebo, it’s testing the difference between people who know they’re not being treated and people who know they are. The result can be a false positive, the appearance of an effect simply because the power of the placebo has been stripped away – in order for it to be a good comparator, in order for a placebo to be a placebo, people need to be unaware of whether they are taking it.
The reviews of the evidence of Viagra are limited in the extent to which they describe whether patients could tell whether they had been given placebos. They are limited both because they do not describe this in detail and because they are reviewing evidence which has not been published in its entirety. Many trials done by drug companies are not made public. Might such distortions of the evidence have resulted in the appearance of chemical effectiveness where none exists?
It’s possible, but there’s reason to think not. The side effects of Viagra are common but not that common. In one review, 12 per cent of people noticed flushing, 11 per cent headaches and 5 per cent some indigestion.16 That compares with an overall success rate for the drug of improved erections for one man in every two that took it.17 For a drug to have a useful effect in half the people who take it is incredibly good. Even if a quarter of people are able to tell by side effects whether they have been given Viagra or placebo, that shouldn’t account for one person in two having a better time of it on the drug.
For the first time in human history, we have an aphrodisiac that works partly as we imagine it to, at least in those with a problem to begin with. But that hasn’t stopped us imagining it works in ways it does not, especially in those who had no circulatory problem holding them back. Viagra works not because it enhances human sexuality but because it eases a certain circulatory problem by which age constricts it. Small and limited improvements, fretted with side effects and drawbacks, are all we can expect from any single medical advance. Even then, intense care is needed if we are to reliably distinguish real effects from observational error, hopeful fantasies, the play of chance and the corrupting hands of vested interests.
With so many Viagra-like drugs approved for men, and such a big financial market for them, there was an obvious next step. Female sexual frigidity was established as a formal psychiatric diagnosis back in 1952. To be dis-eased by lack of libido, to have it subtract from one’s life, is worth attending to whether you are female or male. Declaring it a psychiatric illness is a different thing, and not necessarily a help to taking it seriously and thoughtfully. As the winds of fashion reshaped the sand dunes of psychiatric terminology, the term changed. The most recent alteration was from ‘hypoactive sexual desire disorder’ (HSDD) into ‘female sexual interest/arousal disorder’. The shifting terminology meant a label in search of a market and the market was big.
Enter flibanserin, a drug developed to treat depression.18 Flibanserin had been judged and found ineffective. Spotting an opportunity, Sprout Pharmaceuticals bought the rights. They tried getting the drug licensed for the treatment of HSDD. They failed, since the drug didn’t work.
Undeterred, they tried again. This time Sprout helped fund and organise an advocacy campaign, arguing the previous rejection of flibanserin was a sexist dismissal of women.19 ‘For the millions of women with HSDD,’ wrote a leading female academic, ‘the FDA (Food and Drug Administration) must overcome the problem of institutionalised sexism.’20 The International Society for the Study of Women’s Sexual Health noted the twenty-four drugs already approved for male sexual dysfunction and reported that ‘two-thirds of women polled believe it’s inappropriate that the score is 24–0 when it comes to federal approval of treatments for desire, arousal or orgasm dysfunction in men vs. women’.21 Neither statement, curiously, noted that its author was funded by Sprout.
In the wake of such advocacy, flibanserin was approved for use in the USA. The drug showed minor improvements in sexual happiness, consisting of one additional ‘satisfying sexual event’ per two months. This was criticised as trivial, outweighed by the drug’s known side effects and potential harms.22 There were other reasons for concern. This is a drug that was fixing no known biochemical or physiological error. A review of all the evidence noted the quality of data on which its weakly positive conclusion rested was ‘very low’.23 The review listed its many concerns about how the poor standard of the studies made their conclusion suspect. Researchers had shuffled the outcomes they were looking for, literally moving the goalposts. (Starting out by measuring increases in sexual desire and interest, the study found none whatsoever – so promptly switched to measuring something else, ‘satisfying sexual events’.) Another issue was that it was not clear if the patients taking flibanserin were capable of working out if they had been prescribed the real drug or a matching placebo. Side effects were common and participants were carefully warned what side effects to expect from the actual drug. Without the patients being blind to their allocation, there could be only the false appearance of a control group. Placebo effects on sexual function, as one would expect for experiences that are subjective and modulated by expectation, are huge. Without decent blinding, a weak positive result for flibanserin might even mean the drug worsened people’s sexual lives in a way just barely compensated for by the placebo effect of knowing they were taking it and that it was meant to work.
Forty-eight hours after receiving licensing approval, for a drug whose minimal benefits were widely viewed as not justifying its side effects, and whose benefits may be the illusory result of poor trial design, Sprout sold the rights to flibanserin for a billion dollars.24
*
Intelligence, libido, happiness, industriousness, humour, kindness, mercifulness – for none of these, or anything like them, will there be drugs, machines, rituals, devices or neurotransmitters that allow us mastery. Traits that are properties of human personalities and cultures need to be approached as such. Normal libido can be undermined by lack of hormones, and in those cases it can be fixed by adding them. That cannot be extrapolated to believing normal libido can be enhanced by adding extra. Intelligence can be undermined by lack of hormones – insufficient thyroid hormones in youth lead to the mental disability once called cretinism† – but adding more does nothing helpful. We are persistently over-credulous, and our credulity is another property that will not, despite advances in technology, ever become one that can be tackled with a drug or by gene therapy or some implantable bioprosthetics.
*
Various statistics, unreliable but suggestive, describe patterns of homo- and heterosexuality in different settings. There are even data, a minimal amount, on changes over time.25 None of this adds much to the impression one gets anyway, that we live in a world that has grown more tolerant of sexual variation, and where sexual variation has perhaps increased as a result.
For 150 years at least we have been reaching puberty earlier than ever, the result of better health favouring more rapid growth,26 but at the same time we have become more protective of children, more concerned about early sexual activity. Nothing to regret about either trend, but the stress between them seems worth remarking. Adolescence has been described as a period in which one can practise, relatively safely, for adult sexual life. For evolutionary biologists the notion is based partly on the fact that fertility starts low. This description is accurate but the evolutionary account explaining it is probably false. The eye is capable of perceiving minute amounts of light – an experiment in 2016 reported people detecting single photons.27 Strict evolutionary explanations would describe the selective advantage of being able to do this. Such explanations reduce an observation (‘humans can sense a single photon’) into a discrete characteristic. But attributes are often not just things-in-themselves but epiphenomena. An eye designed to perceive light best in a particular range will show an ability to perceive different amounts of light across a distribution. The extremes – the greatest and least amounts of light it is capable of differentiating – are side effects of the centre of the distribution over which the eye has evolved to function. We are not capable of perceiving single photons because that trait has been selected for, we are capable of doing it because such an ability is the contingent effect of an eye designed to see best at greater intensities of light. Human fertility follows the same normal distribution. Relatively low early fertility is probably not a thing-in-itself, but the rising start of a curve.
Evolutionary explanations of sexuality are not normally useful and they are often not correct. Despite efforts to identify a gay gene, none has been found, nor do patterns of sexuality suggest it is more genetically determined than one’s tastes in politics or footwear. Science can say very little about what sort of behaviour is best, and next to nothing about what’s right. It can peer at these things inasmuch as they cause or reduce happiness and unhappiness, or measurable degrees of sanity and mental illness.
The ages at which we are able to have children will continue to stretch. Parents will continue to have full responsibility for their children without full control; earlier puberty will not, therefore, be without earlier pregnancy. Greater ability to control the hormones that modulate fertility will give us more power to make fertility last or to resurrect it when it has fallen away. Nothing in this technical ability, or in the scientific knowledge that underpins it, will tell us what we should or should not be doing.
Sexual activity does not stop when fertility does. There is a divergence in our species between recreation and procreation. Unlike most other mammals, where females are sexually receptive only when fertile, libido in humans is uncoupled from ovulation. This assertion is not disproven by the fact that careful experiments can show cyclical links between ovulation and female sexual interest. The uncoupling of libido from fertility is amply demonstrated by the need for careful experiments in order to demonstrate any link at all. Sexual life continues as we age, unless impaired by decay or frailty.
Monogamous creatures have lifestyles that are similar for the two sexes. Therefore they look more alike, being built to do more similar things. Those creatures we use as cultural symbols for sexual fidelity, swans and turtle doves, are good examples. Chimpanzees and gorillas are not. Neither are monogamous and both have larger males with large testicles relative to their body size. As with lions and deer, the male’s overall size and power is not there because of extra responsibility for hunting and gathering: it’s there to fight other males in order to gain females. They fight and die in order that their offspring may live. Humans follow the usual mammalian pattern of being sexually dimorphic, with males averaging out as larger, stronger, faster and shorter lived.
There is some relevance of this to our lives today and in the future. The risk-taking and rivalry of adolescent boys seems absolutely part of a half-playful, half-serious jostling for position in a competitive social hierarchy. The greater cardiovascular risk of men is related to their physical power: they can do more at the cost of wearing out more quickly. Such considerations may be helpful when exploring the two, in thinking how to modulate them, and in shaping our expectations for how much we can realistically change without ceasing to be ourselves.
It does nothing to take away from the interest of these observations to note how limited their implications are. If we could establish that we are fundamentally polygamous (or polyandrous), we could make a case for being suspicious of social mores that hold monogamy as the most likely route to a well-lived life. But biological fundamentals and human history are different things. The physical traces of having been recently polygamous tell us little about far more evolutionarily recent human lives and nothing certain about our own. Despite our sexual dimorphism, rates of cheating, based on DNA fingerprinting of offspring, are remarkably low, of the order of 1–2 per cent.28 That compares with figures an order of magnitude higher in birds whose lifestyles are supposedly monogamous.29 Our recent past fails even to predict the current reality of our lives; we should not look to it to discover what lives we wish to lead. To look for moral lessons in our genes is to muddle up categories best kept separate.
*
The appearance – the constituents and constitution – of each sex is not only a reflection of the life it needs to live, it’s a reflection of the sensibilities of the other. We select for what we like and what we love, and by selecting make it.
Darwin wrote of the evolution of aesthetic appearances and the capacity to appreciate them. Sexual selection gave rise to ‘the law of battle’ but it was ‘taste for the beautiful’ by which that battle was fought:
If female birds had been incapable of appreciating the beautiful colours, the ornaments, and voices of their male partners, all the labour and anxiety by the latter in displaying their charms before the females would have been thrown away; and this is impossible to admit... The case of the male Argus Pheasant is eminently interesting, because it affords good evidence that the most refined beauty may serve as a sexual charm, and for no other purpose... the male Argus Pheasant acquired his beauty gradually through the preference of the females during many generations for the more highly ornamented males; the aesthetic capacity of females advanced through exercise or habit just as our own taste is gradually improved.30
The biologist St George Mivart protested that ‘such is the instability of vicious feminine caprice, that no constancy of colouration could be produced by its selective actions’.31 Mivart’s bruised appreciation of female character did not give rise to the only disagreement. Naturalist and explorer Alfred Wallace differed from Darwin in believing firmly in human exceptionalism. What was true for us was not necessarily true for other species. Their intelligence had evolved through natural selection, ours had not. We were driven by a taste for beauty, they weren’t. ‘The only way in which we can account for the observed facts’, he wrote, ‘is by supposing that colour and ornament are strictly correlated with health, vigour, and general fitness to survive.’ He did not mean to include in ‘fitness to survive’ the broader notion of ‘fitness to survive, charm and enthral’.32
Our tastes lead us to select for potential, whose boundaries and contents are not defined by genetics, even though their capacities are underwritten by them. To say that a human has balls can be a great compliment, assuming one is speaking metaphorically. And to speak metaphorically is a reminder that being able to do so is part of the imaginative capacity we have inherited as a result of our forebears bringing it into being through finding it, generation after generation, attractive. To say that our children are our loves incarnate is not to speak metaphorically at all. We are the cumulated manifestations of our ancestors’ tastes. ‘I must study Politicks and War that my sons may have liberty to study Painting and Poetry Mathematicks and Philosophy’, wrote the second American president, John Adams, to his wife. ‘My sons ought to study Mathematicks and Philosophy, Geography, natural History, Naval Architecture, navigation, Commerce and Agriculture, in order to give their Children a right to study Painting, Poetry, Musick, Architecture, Statuary, Tapestry and Porcelaine.’33 Adams would not have written that way had he not believed his wife had a high opinion of the worth of such thoughts, or if he had lacked a desire to display to her the colours of his mind and character.
If women had been designed from scratch there would be no monthly menstruation. It sits in our lives as a relic of our descent from creatures with periodic oestrus, sexually receptive only in their moments of fertility. As sex became less strictly directed at conception, more a part of maintaining the pair bond needed to spend years raising children, the split between fertility and libido widened. A woman’s breasts and buttocks persist in our species in precisely the way a male peacock’s tail does in theirs. They are advertisements of sexual maturity; gloriously (in the eyes of their beholders) wasteful uses of metabolic resources, not efficient parts of physiological design. Breasts in other apes appear only when breastfeeding; in humans, permanent fat appears at adolescence to mimic that appearance. Will changing human tastes lead to changing human bodies? Perhaps, but there are no obvious trends to extrapolate from; there is nothing new under the sun here.
Medicine cannot create beauty or character or fulfilled sexuality but it can help prevent their blemishment. Dysfunction becomes more treatable. The failure to find sexual satisfaction is no longer purely a private or domestic tragedy, rather a problem that can sometimes be tackled with the help of professional aid (or aids, come to that). The heartbreak of childlessness for those who fervently long for children, and the tragedy of losing pregnancies and children that have been so devoutly wished for and loved, has been diminished. It will continue to be.
Some 15 per cent of women do not have children.34 Nor do all conceptions lead to live births. In the first few weeks after conception, fetal loss generally goes unnoticed – a painless and slightly late period is interpreted as being just that, if it is noted at all. For that reason, we have no firm idea how many spontaneous abortions occur so early. It is not even clear the extent to which we would view them as being spontaneous abortions. These very early failures of pregnancy are often due to wildly abnormal mutations: the more abnormal they are, the more they will end before they have properly begun. To lose a half-developed early placenta, containing little or no organised fetal tissue, is not obviously to lose a baby, not when one is unaware and has not invested one’s imagination in hope. Estimates of how many conceptions are lost before they are known vary hugely; in some, the number lost form the majority. From about five weeks of gestation the odds of success, of being born alive, become massively in the baby’s favour. Around 80–90 per cent survive.35 In the early deaths and failures to thrive, evolution retains wide room to operate, as it does in the various fates of our genes as we age and reproduce. Modern life will not eliminate this, nor will technology.
A child growing into itself, full of the self-renewing energy of youth, hides with its own vigour the enormous odds, ‘the play of chance, the capricious fate that energised the inevitability, the number of strokes of luck’36 it took to make it. ‘I wonder sometimes, how did Dad meet Mum, and how did they conceive of me?’37 Nothing is more unlikely in retrospect than the sexual choices that resulted in those most contingent manifestations of all, ourselves. Which is a useful reminder that sexual life is about much more than an act of intercourse, as anyone who has brought up children will fervently vouch. The time it takes to make a baby, sang Billy Bragg, could be the time it takes to make a cup of tea: but the cup of tea is not asking to borrow your car twenty years later. ‘Everything in the world is about sex, except sex,’ goes a famous quote, ‘and sex is about power.’‡ The first part is partly wrong: blue-green algae, happily asexual, would see things differently. The second part, happily, is just wrong. It’s about what you make of it. The tastes of our ancestors, over generations, have made us.
* The trial did show one difference, namely that the period of physiologically enforced flaccidity after an erection was reduced more by the drug than the placebo. It is not clear if this effect, which was marginal, was real or just the upshot of looking for lots of different things in a sea of normal variation. Roll the dice enough times and you get double sixes.
† The name comes from the Swiss French word for Christian: it was meant to be a reminder that those affected were human like the rest of us.
‡ The derivation is unclear.