Social Selection Favors Offspring Prone to the Development of Androgenetic Alopecia

In 2017, a survey of 41 dermatologists reported an increased incidence of male androgenetic alopecia (AGA), particularly in men under 30, with 88% observing this trend. The cause of this increase was unclear, but due to AGA's strong genetic component, a social or environmental factor favoring the inheritance of AGA risk-increasing genes was suspected. The strongest predictor of AGA in men was found to be the length of the CAG repeat in the androgen receptor gene (AR gene) on the X chromosome. The same genetic variant in women was associated with later ovulation, higher antral follicle count, and lower risk for premature ovarian failure. The study theorized that social pressure to conceive later in life gave women with the short CAG repeat in the AR gene a selective advantage, thus favoring male offspring prone to AGA.