Sociobiological theory predicts that the greater variance in reproductive success of males will lead parents with more resources to prefer to raise sons, while parents with fewer resources will prefer daughters. Termporal variations in infant and early childhood mortality rates in a West Indian population do not support the hypothesis that the resources available to parents will affect the relative survivorship of their sons and daughters. It may be that the failure of the sociobiological model is the result of the long post-reproductive survivorship of humans.
Brittain, Ann W.; Morrill, Warren T.; and Kurland, Jeffrey A.
"Parental Choice and Infant Mortality in a West Indian Population,"
5, Article 2.
Available at: http://digitalcommons.wayne.edu/humbiol/vol60/iss5/2