Developmental stages and most common clinical presentation(s) at time of diagnosis

Darker shades of blue correspond to greater likelihood of diagnosis during that time band. The most common period is between ages 20 to 40 years when males with Klinefelter syndrome typically present with infertility (or androgen deficiency). The mean age of diagnosis of Klinefelter syndrome is approximately 30 years. Prepubertal, peripubertal, and adult males with Klinefelter syndrome often have behavioral abnormalities and learning disabilities.