FGF23 and testicular dysgenesis syndrome: Fgf23-/- mice exhibit hypogonadism (DeLuca et al., 2008) and spermatogenic arrest, which resembles the condition of some men with testicular dysgenesis syndrome that occasionally have testicular microcalcifications despite no malignancy (Pedersen et al., 2016; Rebourcet et al., 2014a).