Fertility, Human Birth control 30 Population 28 Family size 12 Statistics 10 Economic aspects 8 Population policy 8 Statistics, Vital 8 Contraception 6 Human reproduction 6 Congresses 5 Fertility 5 History 5 Women 5 Mortality 4 Vital statistics 4 Case studies 3 Population forecasting 3 Research 3 Children 2 Contraceptives 2 Employment 2 Evaluation research (Social action programs) 2 Families 2 Income distribution 2 Infants 2 Mathematical models 2 Population research 2 Social aspects 2 Social surveys 2