Jason Statham's masculinity is enhanced by his lack of hair.
"The suggestion that bald men are more virile than their well-thatched contemporaries is probably an old wives' tale, but it must be conceded that old wives are likely to be unusually authoritative in this matter."
So said the esteemed British dermatologist John Burton back in 1979 when the topic was first explored in the medical literature. Burton was notably balding at this time.
Since the time of Hippocrates it has been known that eunuchs do not go bald. This link between masculinity and baldness was confirmed by the anthropologist James Hamilton in the 1940s when he studied the hair patterns of prison inmates in the United States. He was particularly interested in the sex offenders who had been castrated by the authorities as part of their sentence.
Hamilton found that castration before baldness had developed prevented hair loss completely. Castration after baldness had commenced arrested further progression, but did not reverse the hair loss.
Subsequent research demonstrated that the key hormonal driver of male baldness is testosterone. Testosterone is produced in the male testes, circulates in the blood and binds to the androgen receptor in the hair follicles.
Testosterone is the main androgen hormone, and is also responsible for masculinity, virility, libido and possibly aggression. This link has led to the assumption that baldness is a sign of virility.
John Burton was one of the first to investigate this hypothesis in detail. He looked at testosterone production as well as skin and body reactions to testosterone such as beard growth, sebum production (skin oiliness), sweat production, muscle mass and bone size.
In Burton's study of 48 men aged 35 to 64, surrogate markers of "masculinity" such as hair density on the trunk and limbs, serum testosterone levels, sebum secretion rate, sweat secretion rate, skin thickness, muscle thickness and bone thickness showed no relationship to baldness.
But Burton did not assess virility per se; nor has the baldness/virility hypothesis ever been directly tested since.
Until now. My colleagues and I from the University of Melbourne have now laid this matter to rest by re-examining data from a study originally designed to test risk factors for prostate cancer. The results are published in today's Medical Journal of Australia.
The original study authors recruited 2,836 men with prostate cancer from cancer registers and unaffected controls from electoral registers.
All subjects were interviewed in person and were categorised into four patterns of baldness - nil, receding only, vertex (back of the head) only and fully bald - by the interviewer. These balding patterns broadly capture the different types of male pattern hair loss in Australia.
At the end of the interview, the subjects were given privacy to complete a questionnaire that elicited not only their history of ejaculations obtained by any means between the ages of 20 and 49 but also their number of sexual partners.
The authors found no significant association between baldness (either limited to vertex balding at the crown or being fully bald) and the frequency of ejaculations between age 20 and 49 years. But bald men were significantly less likely to have had more than four female sexual partners.
So, the bad news for bald men is that they are to be no more virile than their well-thatched contemporaries; to the contrary, they seem to have fewer lovers.
While testosterone does cause baldness, the difference between bald men and non-bald men is not how much testosterone they produce, but rather it relates to how the testosterone signal is received in the hair follicle.
Researchers are currently investigating the way genetic differences affect the androgen receptor of bald versus non-bald men.
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Image 1 of 8: Actor Jason Statham.Photo / Creative Commons
* Rodney Sinclair is a professor of Dermatology, Honorary, Epworth Hospital at University of Melbourne.
This article was originally published at The Conversation.
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