Parental age differences.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001722:Birth Order; D004739:England; D005260:Female; D005298:Fertility; D005313:Fetal Death / Q000453:epidemiology; D006801:Humans; D007226:Infant Mortality; D008297:Male; D008423:Maternal Age; D008875:Middle Aged; D010290:Parents; D010334:Paternity; D011247:Pregnancy; D012606:Scotland; D012923:Social Class; D014852:Wales