Part five: High‐Altitude Sex Ratios: How high?

Abstract

The hypothesis that high altitude may be positively associated with unusually high sex ratios is critically assessed. On the basis of a detailed analysis of published and unpublished data on secondary sex ratios in Andean communities derived from censuses and genealogical research, it is argued that sex ratios generally in the highlands of Peru, Ecuador, and Bolivia are only slightly above worldwide norms. Factors that contribute to a modest elevation in sex ratio in this region include a cultural bias in favor of male offspring, underregistration of births, particularly female births, migration patterns, coital frequency, and preferential female infanticide. The high secondary sex ratios found by previous investigators are attributed to faulty data and sampling error.