The second to fourth digit ratio and age at first marriage in semi-nomadic people from Namibia

Abstract

The second to fourth digit ratio (2D:4D) is used as a potentialmarker for prenatal androgen exposure. It is associated with many behavioral and biological variables, including fertility and sexual behavior. However, direct association between 2D:4Dandreproductive success-inpopulationswherenocontraceptives are used-has not been investigated.Here, we present a study conducted among the semi-nomad Himba population living in northern Namibia. 2D:4D ratios were calculated for a sample of this population (N=99;60women,39men),and the results were correlated with age, marital status, age at first marriage, number of children, and number of marriages. As foundinthemajority of previous studies,maleshadlower2D:4D ratios than females. The 2D:4D ratio did not correlate with number of children. Females andmaleswith amoremasculine 2D:4D were married earlier and were more likely to have a husband or wife. We suggest that mating preferences for females with masculine 2D:4D are related to masculinity of phenotypic and personality traits of such women, which are beneficial in harsh environmental conditions and/or higher facial masculinity, which influences the perceived age of an individual. At the same time, masculine (physically strong, dominant, and hardworking) males might gather resources necessary to marry their first wife earlier. © Springer Science+Business Media, LLC 2012.