Secondary sex ratios in Micronesian populations
Underwood, J.H.
Social Biology 40(3-4): 200-206
1993
ISSN/ISBN: 0037-766X PMID: 8178188 DOI: 10.1080/19485565.1993.9988846Document Number: 331928
There have been reports of male:female secondary sex ratios (SSR) from several Micronesian populations which are higher than 109:100 live births. Based upon data from a linked family register of 38,884 records for the native population of Guam before World War II in the Pacific, the authors found an highly masculinized SSR even at high birth orders and parental ages of married fertile couples. These findings contrast with reported declines in SSR with parity and parental age among historical and modern populations in Europe and North America attributed to the effects of decreasing mean coital frequencies associated with marital duration and spousal age. Study findings therefore challenge implicit assumptions about the universality of Euroamerican patterns of marital sex behavior and support the coital frequency hypothesis of SSr determination.