Scant evidence in humans shows an association between MC4R mutations and higher incidence of hypogonadotropic hypogonadism (Hainerová et al., 2011), alterations in the timing of puberty onset (Doulla et al., 2014), and polycystic ovary syndrome (PCOS; Batarfi et al., 2019); however, other studies have shown no association between MC4R and reproductive disorders (Farooqi et al., 2003). This evidence concerns the gene MC4R and hypogonadotropic hypogonadism.