Twins in sibships with Klinefelter's syndrome.
D000293:Adolescent; D000328:Adult; D000368:Aged; D003718:Denmark; D005260:Female; D006801:Humans; D007713:Klinefelter Syndrome / Q000235:genetics*; D008423:Maternal Age; D008875:Middle Aged; D011247:Pregnancy; D013223:Statistics as Topic; D014427:Twins