Natural Age of Consent

If you ask someone on the street what age they think girls prehistoric times typically started having babies they’re likely to answer something like “Oh I dunno, about 12 maybe.” Now, we know this is not true since girls in modern foraging societies don’t typically start reproducing until their mid to late teens even though they don’t use any contraception. So why do so many people think girls in prehistoric times would have started having babies at 12?

What I think is happening is that people are confusing a girl’s readiness to start mating with her readiness to start reproducing. Although girls don’t typically start ovulating and become fertile until 15+ people seem to instinctively think that girls become ready to start mating at about 12. In this sense the age of about 12 seems to be the “natural age of consent”.

Everything changes at about 12

By the age of about 12 most girls are sexually developed enough to distinguish them from pre-pubertal girls and get men’s attention. Women typically report that about 12 was when they noticed that men started taking a sexual interest in them and this is also the most common age women suffer their first sexual assault.

These statistics aren’t unique to modern Western societies. In primitive foraging societies about 12 is when girls become targets for sexual assault. If a girl of this age hasn’t got a husband or other male protector the other men in the tribe will start harassing and sexually assaulting her. To give you an idea how much young adolescent girls are targets for sexual assault in these societies I repeat an experience the anthropologist Kenneth Good had with the Yanomamo people. Good lived with and studied the Yanomamo for years. He fell in love with and married a little girl about 9 called Yarima. These types of romances and marriages between pre-pubertal girls and men are common in primitive foraging societies and are part of the natural human mating system. By the time she was about 12 she’d grown a pair of boobs and he had to protect her from the sexual advances of the other men in the tribe. One day he had to leave the tribe for a few months and worried about what would happen to her while he was away. Before he left he gave a stern warning to the other men to leave her alone, as was the normal practice when a man had to leave his wife unprotected:

Pacing the area I began to speak. “Today I am going away.” I said. I could see they were listening. Most often people just went about their business during a speech, but this was an event. Everyone was looking. “But I am coming back. I am coming back. I am coming back. No one here will break into my storage house. If you do, when I come back I will be very angry. Very angry.” Pause. “And her…” I pointed to Yarima. “No one is to touch her! No one is to touch her! No one!” I could feel the anger coming over me. Pacing up and down, I threw my arms around, slamming myself on the sides and back with my open palm, punctuating the words. “She has been given to me! She is my wife!” Slam! “You do not touch my wife! You do not touch my wife! You do not touch my wife!” Slam! “If I come back and find someone has touched her, I will know!” Slam! “I myself have never touched her! And no one is going to! No one!” I turned around and swung a roundhouse at the wood house pole, smashing it with my fist so hard that the roof shook. Wham! I looked around at all the people in their hammocks, staring into their eyes. They were all staring back. They looked pretty impressed.

At the age of 12 Yarima hadn’t had her first period yet and by the taboos of the Yanomamo the men were supposed to keep their hands off her, but like I’ve mentioned before these taboos are often violated. Good appeared to know this and that Yarima would be a target for sexual assault now she was displaying breasts.

Jailbait at 12, not “post-puberty”

The age of about 12 is also when a girl becomes mature enough to qualify as jailbait. In his 2016 paper on chronophilias Seto characterised the popular jailbait category as post-pubescent minors about 15-17. This is a bit inaccurate, jailbait is usually girls about 12-16. I think he was trying to force the data into the ephebophilia category. Jailbait is not exclusively ephebophilia but just as much hebephilia. The most popular age for jailbait girls is about 14 which is right on the dividing line between the hebephilia and ephebophilia categories.

What makes a girl qualify as jailbait isn’t when she completes puberty, or when she starts ovulating and becomes fertile, or when she starts menstruating, but rather when she simply appears to be ready to start having sex. Typically this is about 12 or 13. This appears to be the age that the females in our species have evolved to become sexually active and this is several years before they typically start ovulating and become able to conceive.

Sex before ovulation

Are human females unique in becoming sexually active several years before they start ovulating? They’re not, we see the same thing in our ape relatives (and maybe most animals?). Chimp and orangutan females don’t start ovulating until about 12-13 but they start mating at about 10. In chimps, our closest relatives, the females typically become sexually active about 2 years after the onset of puberty and it’s likely that ancestral humans followed a similar pattern.

chimp human table

Puberty for prehistoric girls probably followed the same pattern as chimps with mating beginning soon after the onset of puberty and several years before the onset of fertility.

What purpose does it serve for mating to begin before the females start ovulating? The truth is I don’t know. It may be that it has no function. It may just be difficult for evolution to synchronise the onset of mating behaviour with the onset of ovulation. The system works well enough as it is and that’s all that matters. There’s some waste of energy mating when there’s little chance of a conception happening and there’s also some risk a girl may get pregnant early at say 12 and die in childbirth, but these penalties and risks on the whole are very small and maybe just don’t create enough of a selection pressure to weed out genes that cause mating to start happening at these ages. There may be an asymmetry in the costs and penalties so that it’s better for mating to begin slightly before the onset of ovulation than after it. Whatever the explanation it simply appears to be part of the natural human mating system for mating to begin when the females are about 12 or so.

Anticipated questions and comments

-Do you know how dangerous it is for a 12 year old to get pregnant and give birth? How can it possibly be natural for girls to be sexually active at that age?

Because they rarely get pregnant that young, that’s why. This is one of the statistically naive arguments used to try and prove hebephilic relationships would have been maladaptive. If, I repeat, IF a man’s 12yo wife got pregnant she would have suffered greater risks of miscarriage and dying in childbirth than an older teen or adult, but this isn’t what would typically happen. Typically she wouldn’t get pregnant until after 15 when she starts ovulating.

-So we should lower the age of consent to 12 because it’s “natural”? 12 year old girls dying in childbirth doesn’t happen often enough for you to care? Well, that’s nice to hear.

Sigh. I’ve already explained that I’m not arguing for the age of consent to be lowered or anything like it. Personally I do care about 12yo girls dying in childbirth and think we should do what we can to prevent it. My point is that evolution doesn’t care. Evolution is just a dumb statistical process. The rare cases of early pregnancy just don’t seem to have created enough of a selection pressure to remove genes that cause mating to happen at these ages. If you don’t understand that then you need to learn some more about how evolution works.

-As a father this makes a lot of sense to me. When my daughter got to about 12 I became more protective towards her and started being concerned about her getting raped. It was something instinctive.

You’re not alone, the same thing happens to fathers in primitive foraging societies. When your daughter gets to about 12 and she’s grown a pair of boobs you know the other men in the tribe will want to start pushing her around and using her for sex. You’ll have to guard her yourself or get her a husband to do it for you, like Good did with Yarima. In his 2012 paper on the adaptiveness of hebephilia Blanchard tried to use the fact that pubescent girls in primitive foraging societies are closely guarded as evidence that hebephilic preferences are abnormal and I’ve never quite worked that out. The fact pubescent girls have to be closely guarded just goes to show how much they’re sought after by the men and if anything it’s evidence for the normality of hebephilic preferences.

-Have you ever read Lolita? She started having sex at 12 but didn’t get actually pregnant until 17 just like you’re saying ancestral females did.

I know, it struck me when I noticed that. Is it just coincidence or did Nabokov know what he was doing here? He studied zoology and read anthropology so maybe he did.

Next: The adaptiveness of adolescentophilia >>