Black Jamaicans and testosterone

William Aiken:

I wish to propose a hypothesis that addresses not only the aspect of Jamaica's raw athletic talent, but also encompasses an explanation of seemingly diverse phenomena as our high incidence of prostate cancer (one study found it to be by far the highest in the world at 304 / 100,000 men / year), our high crime rate (murder capital of the world status earlier this year), our high road traffic accident and fatality rate, and our alleged high levels of promiscuity.

What do these seemingly disparate phenomena, characteristic of Jamaican life, have in common? On close examination these phenomena are manifestations of high levels of aggressiveness and drive, high libidos, highly efficient muscles from persons of lean body mass and black ethnicity. On closer scrutiny all of these phenomena are either related to high circulating levels of testosterone or alternatively to high levels of responsiveness of testosterone receptors to circulating testosterone.

It has already been shown that the testosterone receptors of blacks are different genetically to those of whites and this difference confers increased responsiveness to testosterone. I propose that Jamaicans of primarily African descent have even greater testosterone responsiveness than blacks anywhere else.

But why should this be? I believe the answer to this lies in the slave ship routes within the Caribbean and the New World.

First, let us assume that all Africans who survived the trek from the African interior to the West African coast and subsequently the middle passage would have been more or less subject to the same inhumane conditions which would have produced a severe selection pressure that enabled only the fittest slaves to survive the journey.

My hypothesis is that for each incremental increase in the journey travelled, once the slave ships entered the Caribbean, there was a corresponding selection pressure which ensured that only the fittest of the fit slaves survived and furthermore the traits which enabled survival were somehow dependent on high levels of responsiveness to testosterone.

Characteristics such as aggression, determination, drive, strong bones, lean body mass, high surface area to body mass ratio, highly efficient and responsive muscles were probably all important for survival and are testosterone-dependent.

Since Jamaica was one of the last stops to be made by the slave ships it ensured that only the most resilient and fittest of slaves were alive to disembark in Jamaica.

This hypothesis is supported by a number of observations. African-Americans and Afro-Caribbean people are represented far more frequently in sprinting events than persons from Africa. Even more interesting is that as one goes westward within the Caribbean, sprinting prowess becomes more prevalent and reaches its peak by the time Jamaica and Bahamas are reached.

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