DATA ON PARENTAL AGE, SIBSHIP, SIZE AND TWINS.
D000375:Aging; D001722:Birth Order; D005190:Family; D005313:Fetal Death; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D010290:Parents; D012723:Sex; D012924:Social Conditions; D013223:Statistics as Topic; D014427:Twins; D014798:Vital Statistics
AGING; BIRTH ORDER; FAMILY; FETAL DEATH; INFANT MORTALITY; SEX; SOCIAL CONDITIONS; STATISTICS; TWINS; VITAL STATISTICS