Human sexuality does not fit the procreation-centric view promulgated by both religion and evolutionary psychology
The procreation-centric view of sex
There are two ways of looking at sex.
From the scientific standpoint, sex is a biological function to procreate, that is, to pass our genes to future generations.
From the personal standpoint, sex is something that we do for pleasure, moved by our sexual desire and our longing for connection and intimacy.
We have been convinced by both science and religion that there is no contradiction between these views.
Science, and in particular evolutionary psychology, tells us that lust and pleasure are caused by behavioral drives to spread our genes. Furthermore, it says that men and women have different reproductive strategies. Men want to have sex with as many women as possible and so have a higher sex drive. Women, on the other hand, are coy and select their sexual partners with care because they make a higher investment in pregnancy and raising the young.
Religions have been promulgating this procreation-centric view of sexuality for centuries. Their puritanical morality says that the only righteous sexual acts are those that produce offspring. However, this sexual morality crashes against our enormous lust, creating endless strife.
Hence, both religion and evolutionary psychology tell us the same thing: “Sex is for making babies and not for your selfish pleasure, you pervert!”
And yet, this belief creates a cognitive dissonance with the way we live. We are the horniest of all mammal species - with the possible exception of our cousins the bonobos. In Western cultures, as sexual liberation advances, we see that women can be as lustful and promiscuous as men, contradicting the prediction of evolutionary psychology.
In fact, when we examine human sexuality more carefully, we find that it departs from the simpleminded predictions of the procreation-centric view in many ways.
I summarize them here as seven enigmas of human sexuality.
Enigma 1: hidden ovulation and lack of estrous in women
If we only fucked to have children, the number of sexual acts we perform in our lives would be much less, by orders of magnitude!
Having 10 children per couple is considered an aberration in our culture, but this was pretty normal in the past, especially considering that many of those children would not make it to adulthood. If a couple has sex twice a week, on average, that would add up to 100 sex acts per year. Considering that a person is sexually active from age 20 to age 60 (an underestimate), then a person fucks on average 4,000 times over his or her lifetime.
All that to have ten children, at most?
Biologically speaking, this is a huge waste. Having sex involves a considerable expenditure of energy. Besides, it was a dangerous activity in our evolutionary environment because it exposed us to predators, aggression from other humans, and sexually transmitted diseases.
The reason why humans have so much sex is that, unlike other mammals, women do not have estrus.
We are all familiar with the fact that dogs, cats, horses, etc. only have sex during a short period, when the female becomes sexually receptive. Otherwise, the female refuses to be mounted and the males are not attracted to her. Even our close cousins chimps, gorillas and orangutans have estrus. Some mammals follow a yearly cycle in which they reproduce and have offspring once a year. That way, they get to gestate when more food is available or during periods of inactivity such as hibernation. This restraint and conservation of resources make sense from the evolutionary standpoint.
Then, why is it not the same in humans?
To deepen the mystery, while females in estrus send out signals to attract males —smells, sexual calls, swelling of genitals, behavioral displays— women do not advertise that they are ovulating. Yes, some women notice it and become hornier during those days, but most women don’t. If women knew when they were ovulating, contraception would be easier and infertility treatments would not require looking at the calendar.
Unlike other mammal females, women are receptive to sex throughout their menstrual cycle. Some women even report being hornier when they menstruate, the time when they are the least fertile.
Why are we different from other mammals in this?
Enigma 2: female orgasms and the location of the clitoris
There are two drives for sex: sexual desire and pleasure.
Most animals experience a compelling impulse to have sex when in estrus, in the case of the female, or when exposed to a female in estrus, in the case of the male. In humans, sexual desire is less compelling but constant.
Animals also seem to experience sexual pleasure during sex, although their copulation is typically much shorter than ours. In humans, sexual pleasure seems to be more intense.
Sexual pleasure seems to be stronger in women than in men. Women’s orgasms are more intense and last longer than the orgasms of men. Moreover, while men have a refractory period after ejaculating, women can have multiple orgasms. It seems that evolution created a stronger motivation for women to have sex.
Evolution did something even weirder to women: it placed the clitoris away from the vagina. This doesn’t make sense. If the goal of sexual pleasure is to motivate sexual intercourse, then the most sensitive source of pleasure should have been placed where it can be stimulated by the penis. Cats, pigs and a lot of other mammals have clitorises inside the vagina.
It is as if evolution wanted to motivate women to masturbate or receive oral sex instead of the old-fashion penis-in-vagina fucking. But masturbation and oral sex don’t make children, so what gives?
Enigma 3: menopause
Not only do women have sex when they are not ovulating, but they also do it after menopause, when they cannot become pregnant. Granted, some women experience a decrease in sexual desire after menopause, but many of them continue to have sexual desire. Most older women maintain a healthy sexual life.
An additional issue is that menopause is unique to humans, being absent in almost all other mammals. The only other animals that have menopause are a few species of toothed whales.
Menopause is not simply becoming too old to get pregnant, but a programmed change in women’s bodies that shuts down ovulation and menstrual cycles in the course of a couple of years. This rather sudden cessation of ovulation does not happen in other mammals. Instead, their estrous cycles become more irregular and infrequent.
Enigma 4: sexual shame and voyeurism
Everybody experiences sexual shame, one way or another. We attribute it to religion and our puritanical upbringing, but it may be deeper than that. Even progressives, skeptics and atheists tend to develop their own forms of sex-shaming as they free themselves from religion. In fact, all human societies seem to consider sex shameful.
In the book of Genesis, sexual shame was one of the punishments for eating the forbidden fruit of knowledge. Sexual taboos change from culture to culture, but there are always some involving being seen naked or having sex. Even in tropical societies that use little clothing, adults cover their genitals.
The flip side of sexual shame is voyeurism. We enjoy watching and hearing others having sex. That’s why porn and erotica are so universally successful. We also like to gossip about sex.
Why do we hide from view when we fuck and at the same time enjoy catching others in the sexual act?
Enigma 5: penis size
The human penis is larger relative to body size than the penises of other mammals. For example, a male gorilla weighs twice as much as a man, but it has a much smaller penis: 3 centimeters or 1.25 inches.
This has been taken as an indication of the overactive sexuality of humans, but there is no real reason for this. Small cocks can give as much pleasure as large ones.
A more accepted hypothesis is that large penises have evolved to attract females, but I fail to see the evolutionary advantage of women being attracted to large cocks. Some women are, but hardly most of them.
A similar idea is that a large penis would intimidate or inspire admiration in competing males. But, again, that does not seem tenable. Men are intimidated by the size and the muscles of other men, but not so much by their penises. Which are hidden in response to sexual taboos most of the time, anyway.
Enigma 6: homosexuality and bisexuality
Since a sex act between two males or two females does not produce offspring, homosexuality should have been quickly culled by natural selection. And yet it is widespread in the animal kingdom.
For example, in his book Chimpanzee Politics the primatologist Frans de Waal documents the sexual behavior of a lesbian chimpanzee. And albatrosses have been seen forming female-female couples. However, some have cautioned about applying human cultural categories to animals.
What is clear is that 8-10% of men or women have purely homosexual behavior, while a larger percentage are bisexual. Women seem to have a greater facility than men to switch over to same-sex acts.
Views of human sexuality centered on procreation have a hard time explaining the emergence of this large amount of homosexual acts.
Enigma 7: fetishism, sadomasochism, dominance-submission and other kinks
Homosexuality is just the beginning of the weirdness of human sexual behavior.
There are many kinks that turn us on, and none of them have anything to do with making babies.
Some people say that anything can be turned into a sexual fetish, but in reality they tend to fall under a few common themes: body parts, clothing, age and power exchange. In their book A Billion Wicked Thoughts: What the Internet Tells Us About Sexual Relationships, Ogi Ogas and Sai Gaddam identified these themes by analyzing internet searches for porn.
Even the most vanilla sex is full of rituals and objects that make it more exciting, like lingerie, candlelight and vibrators. And our sexual lives are not limited to sexual intercourse, but intermingle with our life as flirtations, daydreams and reading erotica. Something similar happens regarding food: we don’t just eat to feed ourselves, but we turn it into the arts of cooking and gastronomy.
Power exchange is an interesting aspect of eroticism. It consists of giving one of the sexual partners power over the other by using bondage, pain (sadomasochism) or psychological domination (dominance-submission). This seems to emphasize an aspect of sex by which the penetrator is seen as dominant and the one being penetrated as submissive. The use of sex to establish social hierarchy is observed in many species of primates, which could be a clue to explain why power exchange is erotic in humans.
In humans, sex was co-opted for bonding
Of course, these seven enigmas are adaptations that ultimately increase our chances of winning the game of natural selection.
However, in the case of the human species the evolutionary logic is not as simple as the narratives commonly presented by evolutionary psychology.
There are two basic reproductive strategies:
Have a lot of offspring and invest very little energy in them,
Have few offspring and take good care of them to increase their chances of survival.
Humans are an extreme case of the second strategy.
There is an important fact that is missed in many discussions of evolutionary psychology.
The reproduction game is not won when we have offspring, but when our offspring is also able to reproduce.
A reproductive strategy that produces lots of offspring that does not survive to adulthood is a losing game.
And this is particularly important in the case of humans. The slow growth of the human brain means that we have to take care of our children for at least 15 years until they reach their reproductive age.
In our evolutionary environment of adaptation, it was impossible for a couple to take care of a child for that long. It took a village to do that. And a village, or a tribe, requires some complex mechanisms to ensure cooperation, discourage selfishness, and establish social hierarchies.
Sex, then, evolved away from its role for straightforward reproduction and into a mechanism for social bonding and the establishment of hierarchy.
Often, during evolution, an organ that evolved for one particular function is co-opted for another. For example, although teeth evolved to tear and mince food, in elephants, narwhals and boars they turned into tusks to be used as weapons.
Similarly, in humans, sex became a tool for social bonding.
How sex for bonding explains the enigmas of human sexuality
Sexual acts became more frequent and women became more interested in them because every sexual act promoted bonding by releasing the social hormone oxytocin.
Ovulation became hidden in women so men wouldn’t know what children were their offspring. Therefore, they became invested in protecting all children of the tribe.
Female orgasms became stronger to motivate women to have sex, compensating them for the risks of pregnancy.
The clitoris became located away from the vagina because non-penetrative sex produces as much bonding as penis-in-vagina sex, while being less dangerous for the health of women.
Menopause evolved because it is more advantageous reproductively for older women to care for their grandchildren than to have more children of their own — the grandmother hypothesis.
Penises grew larger to fit larger vaginas, which are needed to pass the heads of our big-brained babies.
Homosexuality and bisexuality evolved so that same-sex members of the tribe could bond with each other.
Sexual shame, voyeurism and gossip evolved because the social hierarchy of the tribe was established in great measure by who fucked whom. This was not limited to people of the same sex.
Sexual power exchange developed because being the receptive or the active partner during sex became imbued of power symbolism. However, this is not as simple as it seems, because having sex with a person high in the social hierarchy became a way of gaining social status, no matter if it was in a sexually passive or active role. Like grooming in monkeys, who you have sex with designates your place in the social hierarchy of the tribe.
As culture became a critical aspect for survival, sexual rituals, fetishes and taboos became integrated into human sexuality.
Conclusion: human sex is not just for making babies
So there you have it: human sexuality is not just for making babies.
Religions that declare sex-for-fun a sin because “it is not natural” are wrong.
And so are evolutionary psychologists with their simplistic explanations of sex as a competition to see who can have more children, with men and women have conflicting interests in that competition. That may be true for animals, but not for us.
Human sexuality is not a simple biological function, as it is in other animals. It is, literally, “making love” — a profound force that binds us together, not just as couples, but as members of a society crisscrossed by profound erotic currents.
Sex is not an animal act, but a complex and beautiful art that gets integrated into our cultures and makes us uniquely human.
Some of these ideas are defended in the book Sex at Dawn: How We Mate, Why We Stray, and What It Means for Modern Relationships, by Christopher Ryan and Cacilda Jetha.
An opposing view based on the standard view of evolutionary psychology can be found in the book Evolution and Human Sexual Behavior, by Peter Gray and Justin Garcia.
© 2020 Hermes Solenzol
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