I saw on the ‘net somewhere a while back someone had posted a picture that their child had brought home from school. The picture was of a stick-figure human with various lines pointing at it with labels like sex, gender, identity, and sexual orientation. The person who posted this was complaining about the leftist indoctrination their child was receiving at school. They undoubtedly were, but that’s not what was wrong the diagram; it wasn’t wrong for what it contained but for what it omitted. The diagram was implying that sex, sexual orientation, sexual identity, and so on were like a bunch of possible settings that are randomly jumbled together and then randomly distributed to people. What it was missing was any notion that only two combinations are biologically normal and the rest are abnormalities.

I discussed sex in “Sex Is Not A Social Construct” and sexual orientation in “The Myth of Sexual Orientation.” Here I want to put the whole thing together and discuss how the parts fit together in sexuality. Simply put, “biologically normal” or Normal (see Millikan 1984), for short, means the way things have been designed to work by natural selection. Less simply, put it means the conditions that held historically on those occasions where the ancestor of an item was selected by natural selection. Some examples make this easier to understand.

In “Sex Is Not a Social Construct” I used as an example the dances honey bees do when they locate a source of nectar:

When a bee finds a source of nectar it flies back to the hive and does a squiggle dance. The turns and pace of the dance indicate to watching bees the location of the nectar relative to the sun and hive. The perceiving bees then fly off to the location indicated by the dance and retrieve the nectar. That is how the retrieval system is supposed to work, how it is designed to work.

Lots can go wrong however. For one, perhaps the bee misidentifies something as a source of nectar that isn’t one. Maybe it is a plastic flower and not a real one. Or perhaps this bee has a brain parasite and its internal mapping system miscalculates the location of the nectar. Or perhaps the system that translates the bee’s inner directions into dance moves suffers from brain damage so that the bee does a malformed dance. Or perhaps the viewing bees have visual impairment and perceive the dance incorrectly and so fly off in the wrong direction. Or maybe environmental conditions are unfavorable and the bees are blown off course by a tornado. All of these are abnormalities that prevent the dance from performing its function as it was designed to. But none of this shows that the dance wasn’t supposed to map the location of nectar, or that a sperm which doesn’t fertilize an egg wasn’t supposed to, or a heart that can’t pump blood wasn’t supposed to, or camouflage that fails to make an animal invisible to predators wasn’t supposed to.

Examples of Normal functioning can be added endlessly as everything that has been designed by natural selection works according to these principles. Take nutrition. Nutrition is a cycle, but if it can be said to start it starts with the body detecting that it is running low on energy. It then produces a mental instance of hunger, the purpose of which is to get the organism to engage in food-procurement behavior. The organism then procures a source of energy from which it has been designed to be able to extract nutrients. It ingests, chews, and swallows the food, and the stomach further breaks it up, the intestines absorb the nutrients, the blood brings the nutrients to the cells, the leftover waste is excreted. But things can again go wrong at every step. There are people whose brain does not to produce hunger (https://www.livescience.com/48710-boy-never-feels-hungry-or-thirsty.html). Sadly, there are those whose search for food fails and may starve. There are people who ingest indigestible items. There are people with colostomy bags who do not remove wastes the Normal way.

In humans, Normal sexual development begins when the fertilization of an egg by sperm produces XX or XY chromosomes. As discussed in “Sex Is Not A Social Construct,” things can and do fail to work as designed in all biological processes, and the recombination of chromosomes at fertilization is no exception; there are those who can end up with neither XX nor XY. These combinations are abNormal. The growing fetus then develops either a male or female body. Normally, an XY fetus develops male genitalia and a XX fetus develops female genitalia. Any other results are the results of abNormalities. There are a myriad of ways physical development can go wrong. There are those who are born with their heart on the outside (https://www.irishtimes.com/life-and-style/health-family/born-with-her-heart-on-the-outside-vanellope-gets-to-go-home-1.3626550) Someone born with their heart on the outside aren’t differently-hearted; thalidomide babies don’t have a different limb-orientaion; people born without eyes (https://en.wikipedia.org/wiki/Anophthalmia) aren’t eye-non-binary, and so on. In Normal development children contain within them the mechanisms to eventually produce the Normal sex-specific secondary sexual characteristics at puberty. If this does not happen something has gone wrong (https://www.vice.com/en_us/article/9akv47/if-you-are-missing-this-gene-you-dont-go-through-puberty ). When building the brain it is Normal for a the consciousness of a male to identify as a male and to be sexually attracted to females, and the strength of this attraction should correspond to the attractiveness of the female. The same, of course, applies to females. Do I even need to list some of the thousands of ways a brain can malfunction?  There is a strange double-standard in our culture’s understanding of biology when it comes to human sexuality. We can understand how every biological mechanism in the natural world can malfunction except in matter of sexuality. Sexual attraction and, lately, sexual identity are miracles in that they are the only biological processes that are perfect and infallible, I guess.

That is how the sexual system in built. When it is up and running Normally mental occurrences of sexual attraction are the result of the perception of sexually attractive characteristics in a member of the opposite sex. Mental instances of sexual attraction are designed to produce behavior in the pursuit of sex with the specific object of the attraction (a derived proper function), which Normally results in fertilization. Again, Normal does not mean frequent, common, or average. Just as most snowshoe hares still get eaten despite their camouflage having the function to make them invisible to predators, the astronomical majority of instances of sexual attraction fail to produce copulation, and even if they do, the astronomical majority of sperm fail to fertilize eggs. And it should go without saying that we possess a will which allows us to not act on our every impulse.

There are a thousand complications and addendum in the case of human sexuality: people copulating with those they do not find attractive, or copulating out of peer-pressure, pity, greed, or even to spite a rival. Anything that can motivate a human can be a reason to engage in sexual activity.

To return to the stick-figure I mentioned at the outset. In humans it is biologically Normal for an XY individual to develop male genitalia, a male body, to identify as a male, and to be attracted to females. Likewise, it is biologically Normal for an XX individual to develop female genitalia, a female body, and a female brain that produces a sense of identity as a female, and attraction to males. Any other combinations are abNormalities. The Normal expression probably then extends into the cultural realm where sex corresponds to cultural conventions, such as proper attire or behavior for each sex, or cultural icons which possess the semantic value indicating fertility or high mate value.  And so “maleness” refers to anything that follows Normally from being a male and includes genitalia, bodies, brains, psychology, behavior, attire, and so on.  The same goes for femaleness.

Note: none of this has anything to do with morality! It is possible to believe all this and yet believe that there is nothing immoral about homosexuality or trangenderism.

I expect someone might ask “how do you know males are supposed to be attracted to females and vice versa? Who are you to say?” I discuss the rationality of this approach in “The Myth of Sexual Orientation.” I would just say the same would be applied to asking how do we know the heart is supposed to pump blood? How do we know the eye is supposed to produce sight? How do we know the lungs are supposed to pull in oxygen and expel wastes? How do we know babies are supposed to be born with kidneys (http://potterssyndrome.org/) ? You need to produce a theory of what the item does (at least sometimes) that benefits the organism to survive and reproduce. Evidence is collected to show the advantage an item produces. Alternate hypotheses can be tested and the best explanation accepted. In the case of sexuality, by far the best explanation is that sexuality is designed to result in sexual reproduction and the biopsychological sub-systems of the sexual system—sexual attraction, sexual identity—are designed to contribute to this end. In the case of sexuality the overwhelmingly superior explanation (I can’t believe it even needs to be said) is that sexuality is designed to result in sex with a member of the opposite sex so as to result in reproduction. But like all other biological phenomena these processes are susceptible to abNormalities.