Socioeconomic Status and Sex Ratios at Birth in Sweden: No Evidence for a Tri…

Objectives: This study examines if there exists a positive association between socioeconomic status and the proportion of male births in humans, as proposed by Trivers and Willard in 1973, using individual-level data drawn from the complete population of Sweden. Methods: We examine more than 3,000,000 births between 1960 and 2007 using administrative register data with comprehensive informati…