Why are relations between the sexes so complicated?

Note: The subject of this blog post is likely to offend many people. If you think you're one of them the do us all a favor and don't read it.

Disclaimer. Everything in this essay is about my understanding of mainstream heterosexuality. If you disagree, remember that I'm talking about my opinions, not facts. Also, a certain proportion of people wind up homosexual, asexual, or otherwise don't fit the sexual norms. From the surveys I've seen, definitely over 90% and probably over 95% of people are, some experimentation notwithstanding, relatively normal heterosexuals. I have no idea how much or little any of this applies to the remaining minority.

You have been warned.


When I was young I wondered why relations between the sexes are so complicated. After all both genders desire the same thing, why not pair off in some orderly fashion with much less pain and complication? I could see that things didn't work that way, but it seemed to me to be a more sensible way for the world to work than how it actually does.

As I've grown older I've learned about complication after complication. As I learn about complications and see why they happen, the overall picture becomes clearer. Yes, the simpler world I imagined would be convenient, but it can't happen. Why not?

Well let's take my first assumption, that the sexes desire the same thing. We can actually tell what they desire from the questions they ask, and Google correlates those questions and summarizes what they find in autocompletes. When you compare what women and men want their boyfriends and girlfriends to do you get an interesting picture. Men and women want different things.

If we oversimplify, men want sex and women want commitment. Oversimplifying a tad less, men want sex and are willing to provide commitment as a way of getting it, while women want commitment and are willing to provide sex as a way of getting it. If you review the bf/gf comparison and pair the first few questions up, they answer each other in amusing ways. Partially that is coincidence. And partially it is that meeting of different goals.

Evolutionarily that picture makes a lot of sense. It takes little work for men to make children and a lot of work for women to. Therefore biologically men should be selected for a willingness to make children. However raising a human child takes enough effort to need multiple adults. Therefore it is to a woman's advantage to secure that commitment. A man who helps raise his own children benefits his genes, so he should be able to be convinced to do so. The point of lining up help for a woman is to make having children possible, so once the help is lined up, a willingness to have children should follow.

It should be noted that what I've described is not particular to humans. The same evolutionary tendencies and results can be seen in a wide variety of pair bonding species. Though when you apply it to humans people are more likely to be offended than when you describe some type of birds. Though for obvious reasons I find the human case of more personal interest.

It should also be noted very clearly that these strategies are not conscious on the part of the people involved. We have been genetically selected for traits that will cause us to act in these ways. And we directly react to those traits. For instance when a man meets an attractive woman, the parts of his brain that are not associated with libido are invited to take a short vacation. Sometimes with amusing results, such as a temporary inability to speak coherently. He certainly doesn't want this sudden burst of stupidity, but the immediate refocusing of his priorities aligns him with the evolutionarily successful agenda he is literally bred to follow.


Now let's introduce a complication. Sexual partners are not created equal. We have preferences about who of the opposite sex we'd like to have relations with. Preferences vary widely, but some interesting generalizations can be made.

First of all, what do men want? Well health is a good thing. Traits such as clear skin and symmetric faces are signs of a good immune system. Humans have established secondary sexual characteristics such as breasts as signs, and men's attraction to them is obvious. Signs of being good at childbearing as well. Cross-cultural studies have supported the importance of the waist-hip ratio, and even a brief acquaintance with the difficulties of human childbirth with large heads can illustrate why. And, of course, youth.

The subject of attraction to youth is an interesting one. I won't elaborate much on that topic, instead I'll direct your attention to Neotenty and Two-Way Sexual Selection in Human Evolution by David Brin, which is one of the most fascinating pieces of speculation on human evolution that I've read. I don't think he is entirely right, but I think he is right on several things I never thought of until I read that essay. The short summary that doesn't do justice to the essay is that men are attracted to youthful women, which poses the challenge of telling apart young mature women from as yet immature women. We do this through secondary sexual characteristics such as breasts. But this mechanism is fallible, and results in high incidences of pedophilia. (The essay has several parts, I would advise reading all of it.)

Since I have it, I'll give one random instance supporting Brin's thesis from the Google data that I have that he didn't. If you type into Google How do I get my ____ to with either girlfriend or wife in the blank, high among the suggestions will be shave. (Presumably the pubic area is referred to.) Why do so many men want this? Well general lack of hair is a sign of youth. But lack of pubic hair is a direct sign that a woman is not yet sexually mature. Isn't this awfully close to pedophilia?


Moving on, what do women want? Well, obviously, commitment from someone who will be a good care giver. Therefore it is no surprise that cross-cultural surveys (see Brin's essay for a reference) have found that top characteristics women say they desire are kindness, intelligence, and self-confidence. And other desired characteristics include accomplishment, reputation, health, vigor, reliability, and sense of humor. (Random note, the desire to prove accomplishment and reputation pushes men to create many social groups with their own hierarchies that men can try to get on top of.) All of these traits are associated with men who will have the ability and inclination to make good care givers. Note that physical handsomeness is not on the list. Women appreciate it but rate it more lowly, except when looking for extra-marital affairs. (A complication we haven't yet reached.)

Of course the above list isn't complete. For instance there is evidence that women react to pheromones, particularly ones that suggest that a man has a very different immune system. (When people with different immune systems mate, their children are likely to get protection from a broad spectrum of diseases.) Also what women react to and what they say they react to aren't always perfectly aligned, but that detail will have to wait.


OK, time for another complication that causes the pattern to fold in on itself into a pattern of fractal complexity. We have preferences in mates. We each would like to wind up with the best mate(s). But we can't all wind up with the best. Therefore each person tries to wind up with the best person they can, and the extent which we're willing to compromise to get a person depends on the person in question.

What do I mean by this? Well recall that men are aiming for sex, and are willing to provide commitment to get it. Women are aiming for commitment, and are willing to provide sex to get it. The million dollar question as a couple engages is who budges first. In general the higher status the other, the more willing we are to compromise. So the same man who may be willing to claim undying devotion for a chance at a gorgeous woman may be willing to sleep with an unattractive one, but won't commit to her. And a woman who may be willing to have sex with a high status man in hope of commitment may be only willing to have sex with a lower status man after commitment is established.

Tiger Woods provides a good illustration of the latter dynamic. Many women were interested enough in his wealth and talent to give him sexual access. However part of the dynamic was that he tried to make each believe that she was the other woman in his life, so there was a hope that at some point commitment could happen. When the news of his affairs broke and they reach realized how badly they'd been had, they got upset and one by one went public.

Now if you go back and look at the list of traits women want, you have a problem. The characteristics they are looking for are not immediately visible. Therefore women need to read between the lines to establish them. This pushes them towards judging based on secondary traits. For instance a man who is attractive to women who know him well is likely to have several positive characteristics, and therefore is judged as potentially more interesting. And anything that suggests such attractiveness will be seen as positive.

If you read a guide for pickup artists (I highly recommend that every woman should, just so you know what to watch out for), you'll find some odd consequences of this. For instance a man who demonstrates initial disinterest in a woman is demonstrating that he has access to more attractive women. This is evidence that he has what women wants, and therefore must be of more interest. The fastest way to demonstrate disinterest is to make an apparently thoughtless and somewhat insulting comment. If he follows up with nice comments then he has portrayed himself as being of interest but within reach. If the woman believes this message then she is more likely to offer sex without having required commitment first. Which is exactly what the pickup artist wants.

What woman would say that she wants a guy who subtly puts her down? None, obviously. Yet the technique is apparently effective on a lot of women! (Or at least on enough to make pickup artists happy.)


Moving on, what about the way that women tend to be insecure in relationships and the various games they play? I see at least two purposes of these. The first is to test the strength of a man's commitment. It is easy for men to say that they are committed, but if a guy stays through an emotional coaster ride and some demands then he's much more likely to actually be committed. But it isn't simple, because if she pushes it too far, then she has no relationship. How far she can push it will depend on the relationship, which varies widely.

The second purpose is to set clear expectations about how she wants him to behave. This pushes him towards accepting higher levels of commitment, and also makes it clear to him what she will and will not accept.

For an example of a book that helps women use these strategies, see The Rules. I would recommend that all single guys read it so that you can see what you need to defend yourself against. As you'll note from the reviews, it is very controversial, there is roughly an even divide between people who are offended and women who are happy with the men they landed using the strategy.


This brings us to an important point. I am trying to describe the natural dynamics as I see them. Those dynamics tend to be more clear when you look at people who consciously try to manipulate them. The two examples that I've used are pickup artists and The Rules. Most people's natural reaction to those strategies is to dislike how manipulative they are. A second reaction that follows closely is to point out that they result in significant power imbalances. Both reactions are perfectly accurate. They are manipulative and do cause power imbalances. However the manipulation mimics what happens naturally. Power imbalances are common within relationships. The point of the manipulation is to create a power imbalance that gets the manipulator's agenda to the fore. As much as we decry the means, most of us would be interested in the result.


Continuing, let's move on to a tricky complication. Cheating.

It is clear from the basic male agenda why men would cheat. Men cheat because more sexual encounters means more chances to have babies. But women don't want their men to cheat for fear that he'll wind up attached to someone else and leave. And men who are properly bonded will resist cheating, because that is part of what it means to be bonded. So men will not universally cheat, but will at least feel the temptation.

From the basic female agenda, cheating is not immediately obvious. After all it is not a good way to get commitment. But a woman who has a guy doesn't need commitment from anyone else. She has her caregiver, now she wants good genetic material for babies. Cheating offers her two advantages. The first is diversity of genetic material - you never know what combination of genes will work out best and experimentation has value. The second is that she can get superior genetic material than the guy she can get to commit. Of course the downside is that if she gets discovered, she may find herself out of a caregiver.

I've seen widely varying estimates on the levels of cheating in people. I know that some pair-bonded bird species have been found with up to 40% of the population born due to cheating. Humans are hopefully quite a bit lower than that. However one estimate I saw several years ago from England found that about 10% of children are not the children of the person who thought he was the father. That's pretty significant. And in any case it is high enough to contribute to high school biology teachers' reluctance to demonstrate the laws of genetics using the families of their pupils as examples. And is also high enough that a common first reaction among men to seeing his child is to look for a feature that verifies it is truly his. (I've experienced this reaction first hand, and felt silly but did it anyways. I also know someone who noticed that the child wasn't his, with appropriately bad results...)

At this point you get an interesting divergence between men and women. The reasons why men would want relationships and want to cheat are basically the same, so they are attracted to the same women for both purposes. (Though his standards are usually higher for commitment than cheating.) However women are different. A woman is looking for a relationship and affairs for different reasons. Therefore they are attracted to different men for those purposes. In particular for a relationship women want men who they think will make good caregivers. But for affairs women care much more about physical attractiveness. So attractiveness does matter to women, but not in as straightforward a way as it does for men. (Remember that when discussing Brin's essay I said I would come back to the survey result that women care more about appearance for extra-marital affairs than for relationships? Well I just did...)


I could go on but I've rambled quite enough and probably offended a good number of people in the process. Hopefully people found it interesting food for thought, whether or not you agree with all of it. I know that as recently as a few years ago I would have strongly disagreed with several items I stated, and wouldn't be surprised if I disagreed with several others in a few more years.

Did males start as parasites?

Many years ago I was curious about why sexual reproduction is so prevalent. This is a summary of what I found when I investigated.

There is a standard theory to explain sexual reproduction, but it only answers half the question. The standard theory is that a species with sexual reproduction has a pool of genetic diversity. Should the environment change suddenly (temperature changes, a new disease, more effective predators arrive, etc), any gene that helps will have an improved chance of survival and will quickly spread through the population. Without sexual reproduction any particular gene line would eventually go extinct unless it was lucky enough to have the beneficial mutation happen within it. Therefore sexual reproduction allows for much faster adaptation, and benefits the species that does it.

This is all well and good, and convinces me that sexual reproduction has advantages asexual reproduction (as well as being more fun), but it doesn't explain why we have distinct sexes. For instance look at the lowly earthworm. They are hermaphrodites. When they meet they impregnate each other, and both go off and have babies. Hermaphrodites therefore reproduce twice as quickly as a male/female version would. Why, then, aren't we all hermaphrodites?

It can't be a simple quirk of genetics. The genetics of sex reproduction is much more plastic than most people realize. Even if we stick to vertebrates you can find strange things such as hermaphrodites (mangrove killifish) and animals that change gender (African reed frogs, several kinds of fish). So gender is more complicated than the familiar XX vs XY rule for mammals that we learn in biology. If hermaphroditic reproduction was evolutionarily favored, there are enough ways to get there that you'd expect it to be more common than it is.

As it happens I have never encountered a biology text that attempts to tackle this part of the question. However many years ago I came up with a theory that seems reasonable to me. I've discussed this theory with a number of biologists who agree that it seems probable to them as well. So this is my theory, but it is at least plausible. And for all I know it is the standard theory in evolutionary biology, and I just never encountered any source that presented it. (I'm very much not a biologist.)

My theory is that males started as parasites. More precisely, cheaters in a sea of hermaphrodites. And once men were effective enough, the ability of hermaphrodites to impregnate each other atrophied and you got strict sexes.

Let me break this down in more detail.

Imagine a population of hermaphrodites. Now add individuals who can impregnate others, but can't themselves be impregnated. These are males. By refusing the be impregnated the males avoid the hardest part of reproduction. This gives them more energy to devote to impregnating others. As long as the cheater impregnates hermaphrodites twice as fast as hermaphrodites do, this strategy works out.

Evolutionary theory has studied cheating strategies like this. Theory says that in any given environment there will be a natural fraction of the population that is male. With more hermaphrodites/male than the ideal, the male strategy becomes more effective, so the male population will rise. With too few hermaphrodites/male the male strategy becomes less effective so the male population falls. The ideal mix is called the evolutionarily stable strategy. (For another example of an ESS, some salmon fight for the right to spawn, and some try to sneak in while spawning is happening. We can calculate the ideal ratio between how many males should try to fight vs cheat, and it is very close to the actual measured ratios in real salmon.)

If your imagination fails you, don't worry. This isn't a hypothetical possibility, we can find this exact kind of mix of hermaphrodites and males (with no females) in c. elegans. That is a nematode that a lot of biologists study. (Biologists often like to work with organisms that are heavily studied for the simple reason that when they need to know something tangential to their research about how that organism works, there is a good chance that someone else has already studied it.)

In this situation males are cheaters. Biologically in some ways they parallel a virus - they are unable to reproduce on their own but can reproduce by hijacking the reproductive system of their hosts. However biologists have found that symbiosis arises easily out of parasitic relationships. And that is what I believe happened with the genders.

Take our previous population. Imagine that the males are numerous and effective at their job. So effective that a hermaphrodite who attempts to find another hermaphrodite to impregnate will expend so much energy that she would have more children if she just let herself be impregnated more frequently by the very convenient males. In this situation a true female strategy makes sense. And once hermaphrodites take that step, it is only a question of time before the ability for a reproductive individual to play both the male and female parts atrophies, and strict genders emerge.

For more interesting thoughts on sexual differences in humans, here is a psychologist discussing the consequences of men being expendable. I don't agree with all of his conclusions, but he is starting with solid facts that most people aren't aware of. For instance here is confirmation that men are significantly over-represented both at the top and bottom of a lot of distributions.

And in a very different vein, I have long liked David Brin's Neoteny and Two-Way Sexual Selection in Human Evolution. A summary can't do it justice. It comes up with a plausible theory explaining topics as diverse as why women have breasts to why so many men are pedophiles. Even if, no especially if you think that it has to be BS, it is worth the read.