Paternal occupation and offspring sex ratio

Between 1961 and 1997, there were 15 reports of unusual secondary sex ratios related to paternal occupation. Thirteen of these documented a statistically significant predominance of female births (low secondary sex ratios) to fathers working in specific occupations. Findings are summarized, as are authors' suggestions about possible causes for the observed phenomenon. In addition, a new study is reported, replicating the findings of low offspring sex ratios in the children of male anaesthetists. Discussion focuses on four possible explanations of the findings – sampling error, differential damage to sperm, the Trivers and Willard hypothesis (Trivers and Willard 1973 Trivers, R.L. and Willard, D.E. 1973. ‘Natural selection of parental ability to vary the sex ratio of offspring’. Science, 179: 90–92. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), and the maternal dominance hypothesis (Grant 1990 Grant, V.J. 1990. ‘Maternal personality and sex of infant’. British Journal of Medical Psychology, 63: 261–266. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar], 1994 Grant, V.J. 1994. ‘Maternal dominance and the conception of sons’. British Journal of Medical Psychology, 67: 343–351. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar], 1998b Grant V.J. 1998b Maternal Personality, Evolution and the Sex Ratio Routledge London and New York [Google Scholar]).