Primary sex ratio of 125 males to 100 females? Analysis of an artifact

A longitudinal study sponsored by the German Research Society has focused on pregnancy, attendant complications, and resulting fetal and infant development in a total of 13,834 cases from 42 clinics. Data from this project on abortions, miscarriages and stillbirths are evaluated for their respective sex ratios and by several diagnostic procedures, in an attempt to recalculate the primary sex ratio. It is shown that karyotype analysis in the representative sample leads to an estimated primary sex ratio of I to 1, rather than suggesting an excess of male conceptions as formerly believed.