Document Detail

Evolutionary ecology of human birth sex ratio under the compound influence of climate change, famine, economic crises and wars.
MedLine Citation:
PMID:  19719518     Owner:  NLM     Status:  MEDLINE    
1. Human sex ratio at birth at the population level has been suggested to vary according to exogenous stressors such as wars, ambient temperature, ecological disasters and economic crises, but their relative effects on birth sex ratio have not been investigated. It also remains unclear whether such associations represent environmental forcing or adaptive parental response, as parents may produce the sex that has better survival prospects and fitness in a given environmental challenge. 2. We examined the simultaneous role of wars, famine, ambient temperature, economic development and total mortality rate on the annual variation of offspring birth sex ratio and whether this variation, in turn, was related to sex-specific infant mortality rate in Finland during 1865-2003. 3. Our findings show an increased excess of male births during the World War II and during warm years. Instead, economic development, famine, short-lasting Finnish civil war and total mortality rate were not related to birth sex ratio. Moreover, we found no association between annual birth sex ratio and sex-biased infant mortality rate among the concurrent cohort. 4. Our results propose that some exogenous challenges like ambient temperature and war can skew human birth sex ratio and that these deviations likely represent environmental forcing rather than adaptive parental response to such challenges.
Samuli Helle; Samuli Helama; Kalle Lertola
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Publication Detail:
Type:  Historical Article; Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-08-28
Journal Detail:
Title:  The Journal of animal ecology     Volume:  78     ISSN:  1365-2656     ISO Abbreviation:  J Anim Ecol     Publication Date:  2009 Nov 
Date Detail:
Created Date:  2009-10-20     Completed Date:  2010-01-04     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0376574     Medline TA:  J Anim Ecol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1226-33     Citation Subset:  IM    
Section of Ecology, Department of Biology, University of Turku, Turku, Finland.
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MeSH Terms
Climate Change*
History, 19th Century
History, 20th Century
History, 21st Century
Population Dynamics
Selection, Genetic
Sex Ratio*

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