FGF8 and Infertility: Males can be clinically manifested as absent or incomplete puberty, small penis, cryptorchidism, and infertility.12 In the past few years, IHH has classically been categorized as a single‐gene disease,13 but the phenotypic presentation of this disease and its genetic background are highly heterogeneous.14 A few genes that are involved in the pathogenesis of IHH have been identified at various sites, including TAC3, TACR3, GnRHR, FGFR1, GNRH1, FGF8, KISS1, and KISS1R. 11 However, these genetic defects account for less than 30% of patients with IHH.15