Boy, 15-years-old with Kallmann syndrome. His testes were originally undescended, but they descended into the scrotum after human chorionic gonadotropin treatment was given. His height was 163.9 cm (-1.5 SD), and the US:LS ratio was 0.86 (eunuchoid). The penis was 6.3 × 1.8 cm. Each testis was 1 × 2 cm. Plasma LH was not detectable and rose to 5.5 mIU/mL (0.7 ng/mL) after administration of 100 mg of gonadotropin-releasing hormone; FSH rose from 3.6 to 7.2 mIU/mL (1.2-2.4 ng/mL). Testosterone did not change from 17 ng/dL. He had no ability to smell standard odors. (Reproduced, with permission, from Styne DM, Grumbach MM. Reproductive Endocrinology. Yen SSC, Jaffe RB [editors]. Saunders, 1978.)