CONCLUSIONS: After current established treatments with sex steroids, the development of secondary sexual characteristics was mature. However, impaired markers of fertility have been identified in patients with TS, KS and MPHD, reflecting gonadal dysgenesis in TS and KS, but gonadal immaturity in MPHD as gonadal gonadotropin stimulation is lacking throughout development. Consequently, in patients with MPHD, these markers cannot reliably predict individual fertility, which warrants …