Why The Testosterone Surge in Young Boys is a Myth (and what really causes their behaviour to change!)

It’s almost guaranteed to pop up on every parenting related discussion forum, website or chat room you visit.

“Did you know that young boys, around 3, 4 or 5 have a HUGE surge of testosterone? That’s why their behaviour is so difficult at this age”

Seems like a great explanation for the difficult behaviour many parents face at this age doesn’t it?


As a mother of three boys I know what it’s like (but then as a mother of a girl I know she can behave exactly the same). This information seems to trace back to one source,  the book ‘Raising Boys’ by Steve Biddulph. A perpetual bestseller, treasured by hundreds of thousands (millions?) of parents around the world.

Despite the popularity of this information however, I can find no evidence that a testosterone surge in young boys exists, at least not according to my extensive research over the last eight or so years. I’d be happy to proven wrong if anyone can point me elsewhere however? Is it possible that Biddulph’s source was wrong?

It’s something I’ve always felt a little uncomfortable about so I started searching for evidence when my own boys were young (and any unwanted behaviour commonly resulted in people telling me “oh that’s just their testosterone surge”). In my opinion, the idea is right up there with Santa, the Tooth Fairy and the Easter Bunny, beloved statements borne out of our need to pathologise normal child behaviour and remove us of responsibility. Could it be that thousands of parents are being misled about this testosterone surge on a daily basis? Blaming their child’s behaviour on a hormone spike that doesn’t exist?

I’m by no means the only one questioning the existence of the childhood testosterone surge, check out these blogs and discussions too, who all came to the same conclusion as me:






This is an except from a book entitled ‘Gender Equity in the Early Years’ by Naima brown:


Finally here’s a great presentation from a doctor specialising in adolescent medicine who is quick to dismiss the idea that a pre-pubertal testosterone surge exists (check out slide 12):


What Really Happens to Testosterone Levels in Childhood?

Testosterone is an important androgen, or what we more commonly know as sex, hormone produced by both males (in the testes and adrenal glands) and females (in the ovaries and adrenal glands). It is an important hormone for both genders, playing a vital role in bone density and muscle mass, as well as the more obvious development of sexual characteristics.

Immediately after birth the testosterone levels of boy babies are around around 120ng/dl – around half the level of an adult male. They then rise fairly significantly to around 260ng/dl between the second and third month , but then begin to fall very quickly after. By the time the baby boy is 6 months old research shows that his testosterone levels will be extremely low where they will remain until the boy approaches puberty.

The following table shows the changes in testosterone levels as puberty approaches:


I cannot find a single reference to a surge in testosterone in any clinical trial data or medical text book beyond the post birth spike, and believe me I have looked – hard. The only testosterone spurt that is well documented is the one that occurs in the first few months of life.

 Research in 2002 indicates that the famed testosterone surge does not exist post 6 years, with findings showing that:

” Statistical analysis did not prove changes in salivary testosterone concentrations in the preadolescent period of life, with an exception of the insignificant fall at the age of 7 years, and an insignificant rise at the age of 9 years in girls.”

Which led the researchers to conclude that:

“Generally it can be concluded, that salivary testosterone levels in our pre-pubertal subjects remained stable.”

Unfortunately there seems to be no research showing levels between the first few months and this stage, but all lab normal ranges I could find for these age ranges fail to show a spurt. Medical books often contain graphics showing the changes in testosterone levels by age during childhood that look like this however (you’ll note how flat the pre-pubertal section is):


Could there be a danger in attributing a young boy’s behaviour to a testosterone spurt if it does not exist? I think so. I worry that their real needs may not be met if the parent feels that their behaviour is transient and due purely to biology.

What’s Really up With a Four Year Old Boy’s Behaviour Then?

In short – Us, me, you, parents, adults, society……..

We don’t really get normal little boy behaviour, which is strange given that around half of all adults have been one. Little boys (and that is what a four year old is) need to play, play, play, play, play and play some more. They need open space, nature, air. They need trees to climb, balls to kick, mud to squelch, frisbees to throw. They need to be allowed to use their amazing imaginations and explore the world with their whole bodies.

Instead they get school, schedules, strict rules, told to sit still, cooped up inside, taught to read and write, not speak unless they raise their hand and screen time.

These things and four year old boys don’t mix. That’s not the boy child’s fault, it’s totally ours for not understanding or meeting their needs.

So what happens? Frustration and a heck of a lot of it. That can either get internalised (anxiety, depression, insular withdrawn behaviour, sulks and the like), but in the case of most four year old boys it gets externalised (kicking, biting, hitting, throwing, punching, yelling, screaming, whining – you know the ones I mean…) which actually in a way is more healthy than internalising the behaviours, but definitely not socially acceptable.

This frustration has nothing to do with testosterone, lets not blame the failings of modern society onto a chemical. The thing is if we do blame it on testosterone we can appease our conscience, we think “oh it’s OK, little Johnny is just having a testosterone spurt” but that’s dangerous because it stops us from dealing with the REAL issue, which is why I get so very mad at how large and out of control this myth has become.


For those interested in the science and effect of gender on parenting I’d recommend THIS BOOK.

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About SarahOckwell-Smith

Sarah Ockwell-Smith, Parenting author and mother to four.
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20 Responses to Why The Testosterone Surge in Young Boys is a Myth (and what really causes their behaviour to change!)

  1. Sam Vickery says:

    Brilliant article Sarah. It’s just another case of self fulfilling prophecy. Parents hear about this surge in testosterone and are expecting it, so of course they start looking out for it, and begin passing off normal childhood behaviours as symptoms. I think the amount of energy a child has and their need to move, is greatly underestimated in our society, and with just a few extra hours outside running around, so much of that pent up energy would be dispersed resulting in a much calmer, happier child.

  2. Jesse says:

    I’m so glad you wrote this. I cannot count the number of times I’ve been told about testosterone surges in little boys (I have three). And I always thought it sounded dubious. When I looked into it, I came to exactly the same conclusion as you. It all traces back to Steve Biddulph’s book. And there seems to be no supporting evidence.
    Such a shame really.
    Good thing there are so many things to enjoy about being a parent of little boys 😀

  3. penguinsteph says:

    If this is true then I’m not sure what’s happening with my 4yo boy. He is home educated so there is no school, sitting still, raising his hand or strict rules. We have at least an hour and a half of physical activity every morning, outside unless the weather is terrible, and little screen time (30-60 min 2-3 times a week). The rest of the time he is free to play, use his imagination, be read to and have his questions answered (some of which are about what things say or how to write something). But he still has a lot of the problems you describe. Any ideas what’s wrong?

  4. Ilona W. says:

    I’m curious if any of your research explained why little boys need so much play of the kind you described and/or why it’s so markedly different from girls. If it’s not testosterone, what it is?

    • Joshua Koepp says:

      While it’s true that there is not a documented surge at 4 years old in the research you mentioned, please note that there IS a “significant differences between both sexes boys having higher salivary testosterone levels than girls.” The study also mentioned that there were more boys who didn’t follow the “average” but tested much higher: “Testosterone concentrations in girls were normally distributed, but it was not the case for testosterone levels in boys, because of several atypically high values.” I completely agree with your conclusion about boys needing movement and activity. Testosterone is a part of this complex picture. Testosterone does also have an affect on the way boys will handle emotional data.

  5. My son’s attitude and behaviour changed dramatically at the age of four, and I was told about the testosterone thing *after* it happened. He experienced none of the negatives you describe above (my son was at kindergarten for a few days a week, a few hours a day, mostly playing, as he had been since age 3). I’m quite willing to be corrected regarding testosterone, but your explanation misses the mark entirely for my son. Funnily enough he is now 5 and has started school and his behaviour etc have settled and improved and he is his delightful self again! School is perhaps good for him!

  6. Beks says:

    Ive been thinking this is what my son has been going through. It is something i had heard of but was not waiting to happen. It was only when his behaviour changed almost over night and so dramatically that i thought its what it could be. Ive never used the excuse of testosterone surge as an excuse to accept his behaviour i totally dont accept it but all the time outs, marble jar rewards, running around, sporting activities and limited screen time dont seem to be helping. Its a pretty broad generalisation to say everyone who assumes its testosterone surges is using that as an excuse to accept their behaviour.

  7. Steve Biddulph says:

    Dear Sarah, You ought to have contacted me – I have written about this recently including in Juno magazine last edition. I think I am on the same side about boys needing more understanding and scope for energy and creativity, and that society doesn’t allow that enough. Thats been the aim of my forty years work in that area. Here is a quote from a longer response on my Facebook Raising Boys community page. “In response to some criticism though, today I contacted the source for the information in Raising Boys, Professor Mitch Harman, a well known endocrinologist specializing in male development, and Professor of Clinical Medicine at University of Arizona. It was in a magazine article featuring Prof. Harman that I sourced the four year old surge information nearly 20 years ago. Here is his answer…

    “There is a body of work on this subject, and my recollection is that in addition to the well-known high level of testosterone in neonatal boys that declines over the first few months of life, there is a secondary lesser peak of testosterone secretion around the age of 3 to 4. You might find this with a citation or two in a textbook of pediatric endocrinology.”

    I am now searching to see if I can find the primary source. If I can’t find one, we will amend the paragraph in Raising Boys to say so. Its possible that I – and the Professor, are wrong. But I hope people keep on being understanding that at four, for whatever reasons, many boys get stirred up, and we shouldn’t give them a hard time for it, but channel it in good ways so they continue to feel okay about who they are.

    • Hi Steve, thanks for your reply, I have ‘spoken’ with you before on Facebook and asked for your references and you pointed me to your book. If you do manage to find any evidence I would be really interested in reading it and would happily amend this piece. I agree very much with what you say, I’m just a bit miffed that the ‘testosterone theory’ is so widespread when there is (seemingly) no evidence to back it and it is VERY widespread among parenting forums/word of mouth parenting advice. Sadly this results in many parents dismissing their son’s behaviour as “just because of the testosterone”, which I feel does boys a great disservice and could lead to a large proportion of their needs being missed and not met. This I believe undermines a large amount of what you write about which is ironic considering the testosterone belief stemmed from your book! Anyway, thanks for taking the time to respond on this blog, it will be really good for my readers to hear your point of view. Sarah

  8. Steve Biddulph says:

    Are you saying that testosterone (regardless of whether it surges or not) is not responsible for higher activity levels in boys? There’s a circularity in your argument that I can’t quite grasp.

    My experience is that parents respond to the idea with more understanding, channeling their boys energy and finding ways for them to be outdoors more, lessening computer time and so on. I was quite surprised by how many people reacted with such relief to what was just a minor point of interest in Raising Boys when I wrote it. High energy levels in four year old boys was clearly a problem. But I don’t see – in my work, or in any research, any evidence of it being used to “dismiss” behaviour – which still has to be responded to. Just not judgementally or as naughtiness. I think its possible people have run with the idea without the context the book gives as to how to be more boy-friendly. Like you, I don’t like the “boys will be boys” attitudes which are a serious copout. But I think my work has achieved the very thing you are talking about – more sensitivity to boys’ needs, not the reverse. Especially in listening to boys’ feelings and helping them with emotional literacy, which was also the heart of the Secrets of Happy Children book. And Prof. Harman’s reaffirmation of what he was quoted on 20 years ago is not “no evidence”. Its just not the primary source that we need. The original article in the magazine I quoted cited the pico litre levels at that age, about three times the baseline (whereas puberty is closer to eight times, and much more sustained.)

    Blogs and forums will always wander into wild territory, and people change things as they go along. That will happen with the best science. And no science is ever fixed and final, so common sense must also be deployed at all times.

    The studies you cited that didn’t find a spike, only began at age six, a year or two later than we are discussing. And they were based on saliva testing, which is more convenient but not necessarily best practice.

    • I’m saying that pathologising behaviour is an easy ‘get out’ for parents. It’s not you that dismisses it, but them (and they really do!). “Little Jonny’s behaviour seems to have really changed lately, he’s much harder to cope with, my easygoing preschooler has gone and now he’s really naughty, often angry and sometimes quite rude”. “oh, that’s because of his testosterone spurt”. “Oh, thank goodness, it’s nothing I’ve done, so I just need to wait for it to pass and don’t need to do anything, phew!”.

      What if Little Johnny was desperately in need of more connection, more empathy and better communication from his parents, more control/autonomy over his life, a less authoritarian parenting style (yes I know your book advocates this, but I feel it has less of an effect as parents can ‘blame it on the testosterone’). What if there is a problem with nursery/preschool, a new sibling, too much screen time and so on………..one – or all – of these problems are likely to be the cause of the behaviour (which happens in girls too), but if the parent thinks “it’s OK, it’s the testosterone” they are far more likely to ‘ride it out’ and not see the behaviour for what it truly is: a plea for help. The most pervasive argument from your book cited time and time again all over the internet and via word of mouth is not your suggestions (which I think are great) but the testosterone statement!

      So yes, I think it’s damaging. I understand the relief the parents feel, much like those who seek a diagnosis and feel relief that “it’s ADHD” etc… and NOT their parenting. If it IS their parenting, labelling it as a factor out of their control leaves us with millions of boys who may not truly be understood (or helped) and as much of a relief that is to their parents it doesn’t help them.

      Your point about testosterone reflecting in behaviour of young boys is theoretical at best. If indeed there is a large spurt in early childhood (lab normal ranges would show this if it is commonly accepted in endocrinology, I couldn’t find this hence using the only study there seemingly was), what we definitely don’t have is research showing how young boys (not tweens/teens) react to it. So then even IF there IS a huge surge at a four, without evidence to show how 4 year olds react there is a huge extrapolation of a fact. I’m all for theories and if that is your theory it’s an interesting and believable one (because we want to believe it?) – but your book sells it as biological fact. That’s the problem. Does that make more sense? If it was written as “a magazine article suggested a large spurt, but I have found no supporting evidence. That said even if there is no evidence it’s an interesting thought” that would be different.

      As far as parenting goes I’m on the same ‘side’ as you (though I’m not so sure children need different parenting based on their gender), and I really like many of your ideas, I just think it does parents a disservice to include information that may not be true and not to acknowledge it, or at least to acknowledge that it came from a magazine article, not research. I think you hit the nail on the head when you say people take it out of context, they really do and as a stand alone ‘fact’ if it is not correct it really could do more harm than good. I think honestly many people don’t read your book at all – they just blindly quote the testosterone surge statement and think they have to do nothing until nature has run its course.

  9. Steve Biddulph says:

    Dear Sarah,
    I enclose below a detailed response to your last comment on your online blog.
    I am trying to find a good way forward, and so am offering a couple of options. If you are willing to publish the response unmoderated, i.e. in full and without changes, and let that be the final comment on the blog, that would be great. However, I understand that you might not wish to do so. As an alternative, I would be willing to discuss with you an agreed form of apology to go at the top of the blog post, withdrawing any imputation that my work was either deceptive, or harmful. Discussion and debate around parenting is a good thing, but there are reputational factors and when a blog goes worldwide, it has to be scrupulous about not misrepresenting people.


    Your language and thinking is SO woolly, its hard to know where to start.
    You use the term “pathologizing”, which means to make a normal behaviour into an abnormal or problematic one. The explanation of boys’ activity levels as having both a hormonal and cultural basis, which is my position, clearly de-pathologizes them, helping parents understand that its in the nature of children to need free play, exercise and ways to let off steam in an unstructured but safe environment. I am doing – and for thirty years have done – the complete opposite of what you are saying.

    Your lack of a science background is problematic – the testosterone levels you cite, viz “around 260mg/100ml between the second and third month” are wrong by a factor of about 100,000,000,000. Testosterone is measured in nanograms per millilitre. Its a hormone, not a vitamin, and I doubt there is 260 mg in the whole of Essex.

    You quote a study as your centrepiece that doesn’t even cover the age group we are discussing – it is of pre-pubertal children – that is – six to nine – and we are discussing four year olds. You must have noticed this; so to do so without saying so is deceptive.

    Prof. Harman, who was interviewed in the source article for Raising Boys, is a world authority, an endocrinologist specializing in male hormones and their effects. He provided exact levels for the surge in that interview – not as you style it “a huge surge” but an approximate trebling of very low levels for a brief period. Hormones often work like this when triggering a developmental shift, they do their job, and then decline.

    I contacted him last week, twenty years after the research for Raising Boys, and let you know of his reply, which you don’t mention at all in your comment. He confirmed the information about the four year old rise as commonplace.

    That you can’t find something in a few days searching on the internet doesn’t prove it doesn’t exist. Its possible that he, and I are wrong, but you haven’t shown that. The title of your blog is therefore inaccurate. It should be titled The Modest Testosterone Surge in Young Boys May Not Exist. Debating that would have been worthwhile. But it wouldn’t have been so sensational.

    If you don’t believe in gender differences via hormonal or other biological influences, thats your right, and you should state that up front. There are varied views on that, but people need to know where you stand.

    I am concerned that your motivation is self- promotion of your business. That the blog was based on confected anger rather than a genuine wish to advance parenting. Why else would you misrepresent the age range of the study you are quoting?

    Parents will react to information according to their temperament. Those who are lazy or fatalistic may take it as an excuse to do nothing. But I find most parents to be thoughtful, keen to better understand their children, sceptical in a healthy way, but able to take on new information to help them be more open to possiblities – my son isn’t naughty or bad, I am not a bad parent, but here is a factor to consider – he really needs more exercise and less confinement.

    Thats why over a million parents have embraced the messages of Raising Boys and it has improved the lives of their children. It takes a middle road between biology, culture, and the need for social change, which when it was written, was sorely needed, and still, it appears is today.

  10. Steve Biddulph says:

    Thanks for amending the title and some of the content of the original blog Sarah. I am happy now that its a fair discussion and you have corrected the errors. For my part I am writing new content to make sure that parents don’t use testosterone as a reason not to look more widely for reasons why boys’ behaviour may change at this age. On that part, you have a point.

  11. Luke Griffiss-Williams says:

    Anyone I found talking about a testotorine surge was quoting Biddulph. It appears he got confused by the lutenzine hormone. There is a surge in Lutenizing Hormone, which creates the building blocks for testosterone, between the ages of 4 and 6. Effectively, Lutenizing Hormone builds the machine which WILL produce testosterone between the ages of 4 and 6, but that machine doesn’t get switched on until puberty.

    The profiles for LH, FSH, testosterone and Estradiol are different for boys and girls. Lutenizing hormone stimulates leydig cell production of testosterone, it is curious that while there is an increase of LH in boys between 4-6 there is not a corresponding increase in follicle-stimulating hormone, testosterone, or estradiol during this period.

    Debbie Guatelli-Steinbergy and Jennifer Boyce, “The Postnatal Endocrine Surge and Its Effects n Subsequent Sexual Growth” p663-681 in Preedy, Victor R. (editor) Handbook of Growth and Growth Monitoring in Health and Disease NewYork: Springer. (2012)

    Lutenizing Hormone does not have an effect on behaviour, and the most likely reason for “challenging” behaviour at this age is developing independance and sense of self – this is the same for both boys and girls.

  12. Firstly, it think Sarah may be correct that it is a widely perpetuated Myth.. because yesterday (May 2015) a co-worker of mine told me about the “‘big surge of testosterone’ that happens to children around about the age of 4″…. I was interested as I have grandchildren, and in particular an almost 4 year old great nephew who seems to be getting ‘told off’ a lot for quite aggressive behaviour. My co-worker sent me a link. As soon as I read that this statement of ‘fact’ came from Steven Biddulph, I decided to do my own research…. All comments, including the scientific research, I found to be very interesting. And ALL of it, both sides, will be shared with my co-worker and the mother of my nephew. However, I do have a comment on the above debate and conversation between Steven and Sarah. Steven sounds so much more condescending…. his responses to Sarah made me cringe. Background: have read 2 of Steven Biddulphs books many years ago, have raised 2 sons and one daughter. One son was very ‘wild’ and I wished that I had understood him more and could have helped him through his very frustrating school years. One daughter, very physically active, but found it soooo much easier to control and channel her emotions, or at least to conform to society; third son, quieter and gentler and more placid that any of them (until 17!!!).

  13. Hannah says:

    What about an almost four year old who DOES indeed receive tons of outdoor time, imaginative play time, crafts, etc? My “rules” for outside time is basically NO RULES as long as no one is getting hurt. I figure he has enough rules for indoors, although those rules are in essence, don’t hurt anyone and be respectful.
    I am nearly at my wits end with my bright, smart, strong almost 4 year old son.
    I truly do not know what on earth I am doing wrong.
    We were just doing a fun craft and out of no where he threw everything all over the floor.
    This sort of thing happens nearly every ten minutes. He will hit me, kick me and his younger sister etc.
    I am patient, explain why this isn’t ok, and when needed give him time to cool down.
    I work hard to ensure he gets nearly 12 hours of sleep a night, eats healthy decent food, and I try not to let him get overtired or over hungry.
    I just literally do not know what to do. We spend around 3 hours a day outside in our huge yard. I made a mud pit for him to dig in. He runs and uses his imagination.
    I’m just lost. What am I doing wrong?
    I read yesterday about the supposed testosterone surge and was so encouraged but now questioning all of that.
    I haven’t read the above comments yet. So I will do that.
    I love my little boy so much, I hate to see him being so unpleasant, and yet I truly do not know how to get through to him.

  14. Thank you for this post Sarah, I’ve been starting to experience some defiant behaviour from my almost 3 year old son. I asked a few mummy friends if they’d had anything similar and the second reply was about the testosterone spike so I love that I was so easily able to see both sides of the argument.

  15. office mum says:

    I’m writing from the trenches of a hugely stressful few weeks with my 4.5 year old. Hormone surge has been suggested, so I googled to see if it’s true, and found this. Even if it’s not the answer I was hoping for, I prefer knowing the facts! So I guess I need to try more air and playing and open spaces, to make the dreaded school-run more doable… Thank you.

  16. Mary says:

    I too wonder what is going on with my 4.5 year old son. We have very little screen time, live on 4 acres which he is free to roam with his friends and siblings, don’t go to school and eat very healthily (due to allergies, I can’t use most prepackaged foods so make even sauces from scratch). The last few months he’s been so angry and violent. I didn’t know about the testosterone possibility until I read this post. We are very hands on parents, loads of empathy, active listening skills and understand many things on child development and how their brain develops and age appropriate behaviour.
    While I feel better that this is a common thing, I have to wonder that if it’s not for the reasons you describe above, and it’s not testosterone, then what could it be from? Why are so many boys this age in a similar state? I carefully read through all the comments and found there were others in a similar situation. Have you come across any other research to explain it?

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