Sickle Cell Anaemia as a Model for Homosexuality

Sickle Cell Anaemia as a Model for Homosexuality

by David Archibald

1 September 2017


Homosexuality is a conundrum. Theoretically it should be bred out of the population rapidly but instead it persists. There is plenty of evidence that homosexuals are born that way and therefore are part of the human condition. Homosexual males tend to have a longer index finger than middle finger (as heterosexual females do), with the opposite in lesbians.  Birth order affects the incidence of homosexuality, with it increasing with the number of males born to a woman.

So why does humanity include a variant that makes them less likely to reproduce? The answer is that a loss of fitness is acceptable if it brings a greater offsetting benefit. As the incidence of homosexuality increases with the number of sons born to a woman, it appears that it is the result of a variety of immune response to the higher testosterone levels associated with male foetuses. Which in turn suggests that the rate of homosexuality is a trade-off between the loss of reproductive fitness and the maleness of the rest of the crop. In effect, the reproductive fitness of 1.4% of males is sacrificed so that the rest can have higher testosterone levels.

A model for this is sickle cell anaemia, which developed as a genetically inherited disease in response to malaria. The malaria parasite has a complex life cycle and spends part of it in red blood cells. In sickle cell anaemia, a proportion of the red blood cells are shaped like a sickle instead of being rounded. In infected individuals with sickle cell anaemia, the malaria parasite causes the red blood cells to rupture prematurely with the result that the parasite is unable to reproduce. In West Africa, the incidence of sickle cell anaemia is 4 percent. In areas where malaria is a problem, an individual’s chance of survival actually increases if he carries the sickle-cell trait.

Science attempts to explain the universe. The paradox of homosexuality’s loss of fitness is explained the greater offsetting good for normal males.


David Archibald is the author of American Gripen: The Solution to the F-35 Nightmare