Gonadotropins control male and female gonadal function by acting through specific receptors. The recent description of several mutations in LH and FSH receptors has significantly improved our understanding of the pathophysiology of several sexual disorder. Both gain- and loss-of-function germline mutations leading to constitutive receptor activation or to hormone resistance have been described. The clinical impact of these mutant receptors can be markedly different, depending upon the sex of the affected patient and the degree of functional alteration. Numerous mutations were described in LH receptor gene. Constitutive activation of this receptor leads to male-limited precocious pseudopuberty, whereas hypergonadotropic hypogonadism is the clinical phenotype of LH resistance. On the other hand, few mutations of FSH receptor were described so far. Inactivating mutations of FSH receptor are involved in some cases of hypergonadotropic hypogonadism with a more severe impairment of fertility in female patients. Only one gain-of-function mutation of FSH receptor was reported to maintain fertility in one hypophysectomized man. This review is focused on the known genetic alterations of gonadotropic receptors in humans and their impact on male sexual differentiation and fertility.