Socio-economic factors and the sex ratio at birth.
D000328:Adult; D001722:Birth Order; D004522:Educational Status; D005260:Female; D005298:Fertility; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D008297:Male; D011153:Population; D011247:Pregnancy; D011336:Probability; D044469:Racial Groups; D012744:Sex Ratio; D012959:Socioeconomic Factors