Yup. Arm size correlates with how many women a man has slept with in his life, in the past year and how old he was when he first had sex.
On average, men have 61% more muscle mass than women (d=3), a sex difference which is developmentally related to their much higher levels of testosterone. Potential benefits of greater male muscle mass include increased mating opportunities, while potential costs include increased dietary requirements and decreased immune function. Using data on males aged 18–59 years from the third National Health and Nutrition Examination Survey and including other relevant variables, fat-free mass (FFM) and/or limb muscle volume (LMV) are significant predictors of the numbers of total and past-year self-reported sex partners, as well as age at first intercourse. On the cost side, FFM and LMV are strong positive predictors of daily energy intake and strong negative predictors of C-reactive protein and white blood cell count, measures of native immunity.
Source: “Costs and benefits of fat-free muscle mass in men: relationship to mating success, dietary requirements, and native immunity” from Volume 30, Issue 5, Pages 322-328 (September 2009)
If you’re curious about this the science behind mating and sex, check out The Red Queen: Sex and the Evolution of Human Nature.
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