title: Sex ratio at birth deviations in modern Venezuela: the Trivers-Willard effect.
abstract: This study evaluates the impact of the Trivers-Willard (T-W) effect on human populations, using demographic data collected from vital registration data in Venezuela. The evaluation of the sex ratio at birth (SRB) and of fetal and infant deaths supports the existence of T-W effect in the Venezuelan population in extreme conditions. This T-W effect was observable in the SRB but not at later ages and is related to the marital status of the mother. The results indicate that the investment in females associated with environmental adversity is greater than the investment in males associated with good environmental conditions.
authors.affiliation: Department de Ciencia y Technologia del Comportamiento, Universidad Simon Bolivar, Miranda, Venezuela.
authors.forename: G C
authors.initials: GC
authors.lastname: Chacon-Puignau
authors.forename: K
authors.initials: K
authors.lastname: Jaffe
mesh_terms: D015982:Bias; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D016002:Discriminant Analysis; D004777:Environment; D005260:Female; D005313:Fetal Death; D005716:Game Theory; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D008297:Male; D012042:Registries; D012641:Selection, Genetic; D012744:Sex Ratio; D012959:Socioeconomic Factors; D014687:Venezuela