title: Serum testosterone of boys with karyotype 47,XXY (Klinefelter's syndrome) at birth.
mesh_terms: D006801:Humans; D007231:Infant, Newborn; D007621:Karyotyping; D007713:Klinefelter Syndrome / Q000097:blood* / Q000235:genetics; D008297:Male; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone