Sex ratio in Down syndrome.
D003276:Contraceptives, Oral; D003718:Denmark; D004314:Down Syndrome / Q000453:epidemiology*; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008423:Maternal Age; D012042:Registries; D012621:Seasons; D012744:Sex Ratio; D013997:Time Factors
D003276:Contraceptives, Oral