Twins in sibships with Klinefelter's syndrome and the XYY syndrome.
D000293:Adolescent; D000328:Adult; D000368:Aged; D004200:Diseases in Twins / Q000235:genetics; D005260:Female; D006801:Humans; D007713:Klinefelter Syndrome / Q000235:genetics*; D008297:Male; D008423:Maternal Age; D008875:Middle Aged; D010375:Pedigree; D011247:Pregnancy; D012729:Sex Chromosome Aberrations / Q000235:genetics*; D014310:Triplets; D014427:Twins