Twins and Klinefelter's syndrome.
D000328:Adult; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007713:Klinefelter Syndrome / Q000235:genetics*; D008297:Male; D010375:Pedigree; D011247:Pregnancy; D012729:Sex Chromosome Aberrations / Q000209:etiology; D014310:Triplets; D014427:Twins