title: [What are the causes of reduced fertility in human populations in former centuries?].
mesh_terms: D003247:Conservation of Natural Resources; D003710:Demography; D019049:Developed Countries; D004736:Energy-Generating Resources; D004777:Environment; D005060:Europe; D005061:Europe, Eastern; D005298:Fertility; D005523:Food Supply; D005859:Germany, East; D011153:Population; D011157:Population Dynamics; D012621:Seasons; D012942:Social Sciences; D013997:Time Factors
keywords: Demographic Factors; Demography; Developed Countries; Eastern Europe; Energy Supply; Environment; Europe; Fertility--history; Food Supply; German Democratic Republic; Historical Demography; Historical Survey; Natural Resources; Population; Population Dynamics; Seasonal Variation--history; Social Sciences; Time Factors
vernacular_title: Wodurch wurde die Fruchtbarkeit in menschlichen Populationen fruherer Jahrhunderte reduziert.