title: OBSERVATIONS ON TWINNING IN NEW YORK STATE.
mesh_terms: D001719:Birth Certificates; D001722:Birth Order; D001724:Birth Weight; D002869:Chromosome Aberrations; D004899:Erythroblastosis, Fetal; D005260:Female; D005313:Fetal Death; D005333:Fetus; D005826:Genetics, Medical; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D009518:New York; D011247:Pregnancy; D012727:Sex Characteristics; D013223:Statistics as Topic; D014427:Twins
keywords: BIRTH CERTIFICATES; BIRTH ORDER; BIRTH WEIGHT; CHROMOSOME ABNORMALITIES; ERYTHROBLASTOSIS, FETAL; FETAL DEATH; GENETICS, HUMAN; INFANT; INFANT MORTALITY; INFANT, NEWBORN; NEW YORK; PREGNANCY; SEX CHARACTERISTICS; STATISTICS; TWINS