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Interrogating Claims about Natural Sexual Behavior: More on Deep Thinking Hebephile

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In his SciAm post addendum (scroll to the bottom), Jesse Bering has been very gracious. This post really isn’t about that now-infamous advice column, but about broader ways to interrogate claims people make.

This post is another way of thinking about Sci and my #scio12 session on “Sex, gender and controversy” (see our other session posts here and here). When do we use evidence? When do we interrogate claims? When should we rile people up and when do we calm them down? Maybe unpacking the good and the bad from our follow-up posts (because Sci has an excellent one up as well) will provide more fodder for conversation Thursday.

As Scicurious has done in her own post, I am pasting Deep Thinking Hebephile’s original letter in the beginning as a reference:

“I am a non-practicing heterosexual hebephile—and I think most men are—and find living in this society particularly difficult given puritanical, feminist, and parental forces against the normal male sex drive. If sex is generally good for both the body and the brain, then how is a teen having sex with an adult (versus another teen) bad for their mind? I feel like the psychological arguments surrounding the present age of consent laws need to be challenged. My focus is on consensual activity being considered always harmful in the first place. Since the legal notions of consent are based on findings from the soft sciences, shouldn’t we be a little more careful about ruining an adult life in these cases?

—Deep-thinking Hebephile”

“— and I think most men are —”

Deep Thinking Hebephile (DTH) makes the point that “most men are” heterosexual hebephiles. But is this consistent with what we know are the most common preferences and actions of heterosexual men? Further, is this behavior within the range of natural sexual preferences, or is it pathological?

Let’s first be clear on definitions: hebephilia is the sexual preference for pubescent children. Not teenagers, but pubescent children. In industrial and post-industrial populations, that means a sexual preference for ten to twelve year olds, in agricultural populations eleven to fourteen year olds, and in forager populations maybe closer to thirteen to fifteen year olds. Scicurious has already alerted us to studies that negate DTH’s claim that most men are hebephiles. Others that assess sexual preference through a measurable penile response (though in some ways a problematic assessment) show not only high agreement between men’s stated preference for pubescent children and their response to images of them, but that these men are quite small in number (Blanchard et al. 2009).

“…the normal male sex drive.”

Embedded within this idea that “most men” practice hebephilia is the assumption that it is a part of the “normal male sex drive.” If DTH is contending that hebephilia is the normal male sex drive, that implies he thinks it is the natural state for men to prefer pubescent girls.

For something to be naturally occurring, it does not have to be practiced by everybody in a population, so the earlier evidence that hebephilia is uncommon doesn’t necessarily negate this next claim. But for that behavior to continue in some frequency in future generations, it needs to be an evolutionarily stable strategy. So let’s go over the main conditions that would convince me hebephilia is an evolutionarily stable strategy:

  1. Hebephilia is an adaptation: sexual preferences would have to be variable and heritable, and hebephilia itself would need to promote reproductive success under plausible conditions. Further, we would need evidence selection is acting on the sexual preference for pubescent children, rather than a correlated response to a different trait.
  2. Hebephilia is at least equivalent and ideally resistant to alternative reproductive strategies – it needs to be successful enough to beat out most other strategies.

Condition 1: Is hebephilia is naturally selected?

I think the claim could be made that sexual preferences are both variable and heritable – these are the first two conditions necessary for a trait to be naturally selected. For instance, despite very poor support for a “gay gene,” there is strong support that sexual preferences are both heritable and influenced by environment (Jeremy Yoder’s SciAm Guest Blog post on the topic explains this very well). So I am okay with extending this claim to hebephilia, that it very well may be part of sexual preference variation and that it may be heritable. Just keep in mind that hebephilia being part of the range of variation of sexual preferences doesn’t necessarily keep it within the range of normal, appropriate, healthy or socially acceptable.

The third part of natural selection – that the trait must promote reproductive success relative to other strategies – is where the claim breaks down. DTH’s first point, that he thinks most men are heterosexual hebephiles, suggests it is an evolutionarily stable strategy that results in enough reproductive success to continue to succeed among other existing strategies (like, say, a sexual preference for adult women). Perhaps hebephilia couldn’t beat out a preference for adult women (though I am being very generous here, since in a way this is exactly what DTH is trying to argue), but can it at least beat out the other sexual preferences?

I’ve talked about this before, but girls just past menarche (that’s her first period) are usually what’s called “subfecund” – this means that fewer of her cycles, when she does cycle, are ovulatory, compared to an adult woman. In fact, the most consistent ovulatory cycles and highest hormone concentrations are found in women 25-35 years old, shattering the myth that younger women are actually the most fertile (Ellison et al. 1993).*

So it is harder to get pregnant if you are just past menarche. And since the definition of hebephilia is attraction to a pubescent child, this includes attraction to and sex with girls who haven’t necessarily even had a period yet – girls who are completely infertile. If you are going to bet your reproductive success on one partner age, pubescent girls are probably the wrong one.

The second issue is that very young teen pregnancies have pretty negative health outcomes. Girls who give birth over sixteen or seventeen don’t experience any more negative birth outcomes than those over eighteen, but girls under fourteen – which, again, fits the hebephilia preference for pubescence – have increased risk of maternal and infant mortality (Kramer 2008). Further, the higher rates of infant mortality in those girls who first give birth under fourteen years of age can therefore expect a lower number of surviving children out of the total number they bear (Kramer 2008, Figure 1).

Graph demonstrating that girls who begin giving birth as young adolescents have lower reproductive success in relation to total parity

Kramer 2008 Fig 4. Graph demonstrating that girls who begin giving birth as young adolescents have lower reproductive success in relation to total parity

Now remember, these data come not from the “puritanical, feminist” American culture, but from a rural, traditional Mayan culture. But these data do support those found in industrialized populations found in a simple Google Scholar search. This search revealed a wealth of data showing that very young girls having babies doesn’t happen much, and when it happens it doesn’t often end well (Chen et al. 2007, Duenhoelter et al. 1975, Felice et al. 1981, Fraser et al. 1995, Haiek and Lederman 1989, Merritt et al. 1980, Olausson et al. 1999).

Condition 2: Is hebephilia resistant to alternative strategies?

For hebephilia to be an evolutionarily stable strategy, it needs to beat out other strategies. Already we are in danger of this strategy losing out because young teen pregnancies are far less successful than older teen and adult pregnancies. But let’s put a few more nails in the coffin.

We know of past and current cultures where older men marry pubescent, even pre-pubescent girls. However, hebephilia is defined as an adult who wants to have sex with pubescent children. This is not the same as an adult man who wants to marry a twelve year old girl and not have sex with her until she is older, for the purpose of securing a dowry or piece of land or better relationship with her family. That is common throughout human history. We cannot use as justification the few marriages in the Middle Ages (or partnerships in traditional forager societies) that happen to involve pubescent girls, because they rarely, if ever, involve sex with the child until she is older.

The example I know best is from the classic !Kung ethnography Nisa by Marjorie Shostak (1983). In this book, Nisa narrates how she is forced to marry an older man before she hits menarche. She runs away to her family several times, and her family is very permissive of this behavior. After a while, they demand she grow up and live with him. And she more or less does. Nisa eventually gets her first period and the menstrual celebration commences. It is only after this point that she is pressured to have sex with her husband. And eventually, she does.

Sex with pubescent girls appears to be highly infrequent. In Kramer’s paper on birth outcomes in teen pregnancies in traditional Mayan population, she reviews this exactly literature (2008). She finds:

“In natural fertility populations, the lapse between menarche and exposure to conception is highly variable, and may last one to two years up to over a decade (Whiting et al., 1986; Schlegel, 1995)” (Kramer 2008: 346).

And yes, she’s being nice about it, but by “exposure to conception” Kramer is talking about straight sexual activity. So in traditional, natural fertility populations (where natural fertility generally means non-contracepting) girls tend not to have sex, on the lower end of the spectrum, until a few years after menarche. That is post-pubertal, which means non-hebephilic.

Finally, there are definitely strategies that beat out hebephilia. There are two main mating strategies to secure a high chance for reproductive success if you’re male: to control the fertility of a female starting early, or to find a female who already has demonstrable reproductive success – a mother. Our closest primate relatives generally choose the latter: male chimpanzees don’t salivate over adolescent female chimps, and in fact reject them as sexual partners quite frequently. Instead, male primates and other animals fight over sex with the older females who’ve already borne a kid or two (Anderson 1986, Muller et al. 2006, Nichols et al. 2010, Proctor et al. 2011, Robbins 1999).

In humans we see plenty of individuals choose between either strategy and both can be quite successful. The former strategy is not unlike the one Nisa’s husband employed: marry the girl he wants, but don’t actually have sex with her until she comes of age. Of course, DTH will be sad to know that many consider this strategy to control female fertility part of a suite of behaviors that helps us understand the evolution of patriarchy (Smuts 1995).

At the end of the day, neither condition is supported. Hebephilia is not a direct product of natural selection, nor is it a successful strategy compared to other existing ones. DTH cannot get the satisfaction and validation he so desperately wants, because no matter how much he wants to justify it to himself, it cannot be justified in the context of the scientific evidence. Even if somehow this evidence were overturned by a wealth of opposing data, hebephilia is still not a permissible behavior, and it’s important to remember to make the distinction between what we can observe within human behavior, and what is right.


I would like to thank Scicurious and Charles Roseman for their comments on an earlier draft of this post.


*Subfecund is still fecund, and age-based probabilities are still probabilities. Don’t let these data fool any individual into ever thinking unprotected straight sex when a woman is postmenarcheal and premenopausal has few or no babymaking strings attached!


Anderson, C. 1986. Female age: Male preference and reproductive success in primates. International Journal of Primatology 7:305-326.

Blanchard, R., A. D. Lykins, D. Wherrett, M. E. Kuban, J. M. Cantor, T. Blak, R. Dickey and P. E. Klassen. 2009. Pedophilia, hebephilia, and the DSM-V. Archives of Sexual Behavior 38:335-350.

Chen, X.-K., S. W. Wen, N. Fleming, K. Demissie, G. G. Rhoads and M. Walker. 2007. Teenage pregnancy and adverse birth outcomes: a large population based retrospective cohort study. International Journal of Epidemiology 36:368-373.

Duenhoelter, J. H., J. M. Jimenez and G. BAUMANN. 1975. Pregnancy performance of patients under fifteen years of age. Obstetrics & Gynecology 46:49.

Ellison, P. T., C. Panter-Brick, S. F. Lipson and M. T. O’Rourke. 1993. The ecological context of human ovarian function. Human Reproduction 8:2248-2258.

Felice, M. E., J. L. Granados, I. G. Ances, R. Hebel, L. M. Roeder and F. P. Heald. 1981. The young pregnant teenager*,**:: Impact of comprehensive prenatal care. Journal of Adolescent Health Care 1:193-197.

Fraser, A. M., J. E. Brockert and R. H. Ward. 1995. Association of young maternal age with adverse reproductive outcomes. New England Journal of Medicine 332:1113-1118.

Haiek, L. and S. A. Lederman. 1989. The relationship between maternal weight for height and term birth weight in teens and adult women. Journal of Adolescent Health Care 10:16-22.

Kramer, K. L. 2008. Early sexual maturity among Pume foragers of Venezuela: Fitness implications of teen motherhood. American Journal of Physical Anthropology 136:338-350.

Merritt, T. A., R. A. Lawrence and R. L. Naeye. 1980. The infants of adolescent mothers. Pediatric annals 9:100.

Muller, M. N., M. E. Thompson and R. W. Wrangham. 2006. Male chimpanzees prefer mating with old females. Current Biology 16:2234-2238.

Nichols, H. J., W. Amos, M. A. Cant, M. B. V. Bell and S. J. Hodge. 2010. Top males gain high reproductive success by guarding more successful females in a cooperatively breeding mongoose. Animal Behaviour 80:649-657.

Olausson, P. O., S. Cnattingius and B. Haglund. 1999. Teenage pregnancies and risk of late fetal death and infant mortality. BJOG: An International Journal of Obstetrics & Gynaecology 106:116-121.

Proctor, D. P., S. P. Lambeth, S. J. Schapiro and S. F. Brosnan. 2011. Male chimpanzees’ grooming rates vary by female age, parity, and fertility status. American Journal of Primatology

Robbins, M. M. 1999. Male mating patterns in wild multimale mountain gorilla groups. Animal Behaviour 57:1013-1020.

Smuts, B. 1995. The Evolutionary Origins of Patriarchy. Human Nature-an Interdisciplinary Biosocial Perspective 6:1-32.

Kate Clancy About the Author: Dr. Kate Clancy is an Assistant Professor of Anthropology at the University of Illinois. She studies the evolutionary medicine of women’s reproductive physiology, and blogs about her field, the evolution of human behavior and issues for women in science. Find her comment policy here. Follow on Twitter @KateClancy.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. Kapitano 2:02 pm 01/18/2012

    “he thinks it is the natural state for men to prefer pubescent girls.”

    Does he? Two points.

    First, you define ‘pubescent’ as aged 10-12. He specifically talks about teenagers. You even quote him talking about teenagers, then write about him as though he’d talked about girls of 10-12.

    Second, there’s a difference between being attracted to a range of ages that extends down to the teens, and being primarily or solely attracted to teens. Which is ‘Deep-thinking Hebephile’? It’s not actually clear from what he wrote, but you jump to the second interpretation.

    As for your slightly strange argument that hebephillia is bad evolutionary strategy, therefore it’s morally wrong, others can go into it.

    I’ll just say that if it’s abhorrent, it’s abhorrent because it’s child abuse.

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  2. 2. kclancy 2:37 pm 01/18/2012

    When DHT says that “most men’s” “normal” sex drive is to be a hebephile, then yes, it does appear that he is saying it is natural. Further, the definition of hebephilia is preference for pubescent children. DHT may want to try and characterize this as liking “teens,” but it is simply not the case.

    As for your conflating my two arguments, first that hebephilia is a bad evolutionary strategy, and second that it is morally wrong, I suggest a closer reading of the post.

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  3. 3. scicurious 2:46 pm 01/18/2012

    Really interesting post, Kate, I’m glad we were each able to approach this issue from such different angles!

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  4. 4. whosyourboi 4:16 pm 01/18/2012

    I think I have to agree with kapitano on some points; those are that:

    you do appear to have conflated the arguments that hebephilia is immoral and that it is maladaptive or a pathology.

    and that if it is morally reprehensible it is because it is child abuse.

    However, the reason I wanted to comment was to sound you out on a thought. If there is some kind of normal distribution for male preference about a ‘prime’ of female fertility then maybe hebephilia isn’t so much a pathology as one extreme of this distribution, more of an outlier?

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  5. 5. gregdowney 5:44 pm 01/18/2012

    Great post, Kate. I think that the criticism that you are conflating statements of ‘morality’ with statements of what is ‘natural’ or ‘adaptive’ is part of a larger problem; so often, these switches are made pretty much without comment in the discussion of ‘human nature’ or ‘sexual nature.’

    Personally, I don’t think you’re guilty of it, but as a bio-cultural anthropologist, it seems that it’s hard to write anything about human sexuality, especially, and not have someone read ‘natural’ for ‘morally correct’ or vice versa. I don’t think I have any solution to this, but the issue doesn’t seem to arise so much except when talking about sex (and a few other issues), and seems to me is quite likely a bit of a hangover from ‘natural law’ concepts. In other words, we may be able to blame this on Thomas Aquinas, if we want.

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  6. 6. countryphd 10:25 pm 01/18/2012

    I would like to make two comments.

    First, I would agree with kapitano. You are at cross purposes with Deep Thinking Hebephile. He speaks of teens; you, of what we would normally call sub-teens. It may be he misunderstands the proper definition of “hebephile.” Your post i, an excellent response to his claim assuming that term had been correctly used, but it is not a response to the claim he actually appears to be making–that most men prefer teenage females. I have not studied such things, but, if we consider the evidence from Ogas and Gaddam’s A Billion Wicked Thoughts, there does appear to be some reason to believe that many, if not most, heterosexual men have a strong attraction to, if not a preference for, teenage females.

    Secondly, I wonder if the scope of your argument with respect to stable evolutionary strategies is not too limited. Considered by themselves, excessively large antlers and extraordinarily long, trailing tail feathers would appear to be obviously maladaptive strategies, but the succeed and are stable. The question is only which males reproduce. Perhaps hebephilia leads to low rates of female reproduction, but getting to the female first might, despite that, yield a reproductive advantage to the male. This strategy might not beat out all other strategies, but it might well be a successful and relatively stable sub-strategy.

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  7. 7. kclancy 11:37 am 01/19/2012

    Here’s my thought about this. DTH uses the term hebephile, and since it is such a parsing of pedophilia I suspect he know exactly the definition, and exactly that his preferences are indeed of children. He may use the term ‘teen’ to divert attention from this reality and confuse the conversation, maybe even to make himself feel better. But they are not teens.

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  8. 8. Kapitano 1:05 pm 01/19/2012

    @kclancy: he know exactly the definition, and exactly that his preferences are indeed of children. He may use the term ‘teen’ to divert attention from this reality and confuse the conversation

    You are now arguing “DTH said X, but what he really meant was Y, and any evidence to the contrary is deliberate comouflage by DTH. Y is wrong, so I’ve disproven DTH’s reasoning.”

    Not just a strawman but, to borrow a term from TV Tropes, a lampshaded strawman.

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  9. 9. Fem_Panduh_er 3:39 pm 01/19/2012

    THANK YOU. We finally have the final word on this so we don’t have to debate interpretations, biases and laws on all this messy stuff. Bookmarked!

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  10. 10. Philosophe22 3:12 pm 01/20/2012

    @Kapitano You are ignoring the fact that he also used the term “hebephile.” “I am a non-practicing heterosexual hebephile”. Talk about lampshades…were you able to write your nonsensical post without blushing?

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  11. 11. CherryBombSim 7:53 pm 01/20/2012

    You have gone to a lot of trouble to show that hebephilia can’t possibly be an adaptation, but what are you trying to prove by this? That hebephilia doesn’t exist? It clearly does, at least in some people.

    There is an unspoken assumption that a lot of people make that any behavior that they can label, like “hebephilia”, is a discrete trait that responds to selection pressure. Behavior is not a trait. Behavior is what you *observe* when evolved traits interact with environment.

    DTH’s behavior might be socially unacceptable, but so is knocking over liquor stores. Humans have not evolved to rob liquor stores as a successful evolutionary strategy (I think), it is emergent behavior. We don’t need to worry about whether it is an adaptive trait or not to justify discouraging it.

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  12. 12. henrykaminer 9:01 pm 01/24/2012

    The discussion so far is erudite but neglects two areas. First, the Human species in many ways alters its own environment so that the discussions about adaptation based on age of menarche, relative success at reproduction, etc., you all ignore that for example a powerful dictator can prevent reproductive success and reserve all the women for himself- and he may choose to mate mainly with ten year olds and mate occasionally with older women to produce more children. May I mention the Royal Family of an oil-rich kingdom that is our nominal ally? Second, we must consider the Mental Meaning of these actions- we are thinking creatures, even if we hide our true motives from ourselves. How OLD is DTH? we do not know. Therefore, WHY does he prefer these young girls? There is no evidence that most adult men share his desires! On the other hand, there is Much evidence from psychoanalytic studies and from psychological testing protocols that adult men who strongly prefer such young females have a characteristic set of reasons that have nothing to do with reproductive success, evolution, or innate biological variation. The findings, repeated many times over the past one hundred years, show that these men are basically afraid of mature women, are fearful of their own (imagined) sexual inadequacy, and need to feel power and control of the sexual encounter. They need the girl to be in awe of their sexuality. By the way, a milder form of these ideas is responsible for the fetish of virginity- that is, men can have experience but they want a woman who has no prior sexual experience- so she cannot judge his adequacy and prefer his imaginary rival! Enough about this- just remember Humans have minds and have unconscious mental contents as well as conscious mental contents.

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  13. 13. Eleanor100 5:02 am 01/25/2012

    Excellent post, Kate. I think you’ve got the ESS and evolution side right. I don’t you making value judgements, maybe people are conflating ‘natural’ and ‘right’ or something.
    By verbal theoretical arguements, it seems pretty clear that going for sub-fertile females is unlikely to be the dominant stable strategy either in systems where males compete for females or where males can monopolize access to females, as in both scenarios males reduce their chances of successful matings. At the most, you could could argue that low-value males unable to compete successfully in male-male competitions might mate with sub-fertile females in a ‘best of a bad job’ type scenario. However, I bet you couldn’t construct a (mathematical) model where this was actually a stable strategy in the population.
    As a side note, it’s a bit weird that the popular perception of mate choice is still on the Victorian notion of “monopolising males”, rather than “choosey females”. Neither is correct, it just seems… odd.

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  14. 14. Sue W 9:52 am 01/27/2012

    Interesting post, although analyzing what we used to call a dirty old man somewhat too seriously IMO. Lolita is a true-life horror story, surely.

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  15. 15. lamcnam 11:43 pm 02/12/2012

    Kate, your blog response was thorough and erudite, but I was equally fascinated by the initiating letter from the Deep-thinking Hebephile. His argument is replete with cognitive biases, including belief bias, confirmation bias, even a valence effect (“If sex is generally good for both body and brain…”).

    In this case, unfortunately, it’s a small step from from cognitive bias to thoughtful justification of full-on child abuse. I’d certainly not let this person near my children. And I’m not sure that any amount of erudite, scholarly response would ever change this individual’s mind (he’s already engaging in quite a strong form of subjective validation).

    But hopefully anyone who’s meandering around the Interwebz looking for “scientific” justification for hebephilia will read your essay and think twice before equating “within the range of human evolutionary variation” with “it’s okay to deflower a thirteen-year-old.”

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  16. 16. peftuspeftus 12:33 am 03/3/2012

    Kate, short of CherryBombSim’s take (which seems by all accounts to be accurate), there’s an even more basic level at which your argument fails either by deliberate disingenuousness or by plain old ignorance. There is a third path by which any behavior or even allele may remain evolutionarily stable over long periods: namely, by close linkage (whether by chromosomal locus or otherwise) with other behaviors or genes that experience consistent strong selection. To omit this possibility is not just a way in which your argument loses relevance at higher levels of analysis, but rather is a failure within your argument itself as you constructed it. We can do better.

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