Effect of age on testicular function in patients with Klinefelter's syndrome

Testicular function in the patient with Klinefelter's syndrome parallels the alterations seen with age in the normal subject. Significant decreases are seen in the Klinefelter group in the plasma level of testosterone and in the plasma testosterone/oestradiol ratio. Testicular function in the patient with Klinefelter's syndrome appears very much like that seen in a chronologically older subject.