Secular Trends in Sex Ratios at Birth in North America and Europe over the Second Half of the 20th Century

Overview

Journal J Epidemiol Community Health

Specialty Health Services

Date 2003 Jul 29

PMID 12883068

Citations 17

Authors

V Grech

P Vassallo-Agius

C Savona-Ventura

Affiliations

Soon will be listed here.

Abstract

Context: A previous study showed that significantly more boys were born in southern latitudes in Europe than in northern latitudes and the converse pattern was observed in North America.

Objective: This study analyses secular trends in gender ratios for live births over the second half of the 20th century.

Design, Setting, Participants: Analysis was carried out from a World Health Organisation dataset comprising live births over the above period. This included 127034732 North American and 157947117 European live births.

Main Outcome Measures: Analysis of trends in gender ratios for countries in both continents.

Results: The findings show a highly significant overall decline in male births in both Europe and North America (p<0.0001), particularly in Mexico (p<0.0001). Interestingly, in Europe, male births declined in North European countries (latitude>40 degrees, p<0.0001) while rising in Mediterranean countries (latitude congruent with 35-40 degrees, p<0.0001). These trends produced an overall European male live birth deficit 238693 and a North American deficit of 954714 (total male live birth deficit 1193407).

Conclusions: No reasonable explanation/s for the observed trends have been identified and the causes for these trends may well be multifactorial.

Citing Articles

Sex ratio at birth across 100 years in Sweden and risk of cardiovascular disease and all-cause mortality - a national register study.

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Systematic assessment of the sex ratio at birth for all countries and estimation of national imbalances and regional reference levels.

Chao F, Gerland P, Cook A, Alkema L Proc Natl Acad Sci U S A. 2019; 116(19):9303-9311.

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Revisiting the Trivers-Willard theory on birth sex ratio bias: Role of paternal condition in a Malagasy primate.

Perret M PLoS One. 2018; 13(12):e0209640.

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Maternal and paternal serum concentrations of persistent organic pollutants and the secondary sex ratio: A population-based preconception cohort study.

Bae J, Kim S, Barr D, Buck Louis G Environ Res. 2017; 161:9-16.

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Live birth sex ratios and father's geographic origins in Jerusalem, 1964-1976.

Groeger J, Opler M, Kleinhaus K, Perrin M, Calderon-Margalit R, Manor O Am J Hum Biol. 2016; 29(3).

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