title: Familial studies of monozygotic twinning.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D005826:Genetics, Medical; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D008875:Middle Aged; D010375:Pedigree; D010920:Placenta; D010929:Placentation; D011247:Pregnancy; D044469:Racial Groups; D014427:Twins; D014430:Twins, Monozygotic