RecruitingPhase 3Drug trialSex Steroids Balance for Metabolic and Reproductive Health in Klinefelter SyndromeThe study seeks primarily to determine whether modulation of systemic and testicular sex steroids balance by aromatase inhibitors will positively affect the metabolic health and spermatogenesis of men with Klinefelter syndrome (KFS) as compared to the current state of the art for each issue. Secondary objectives of this study are (i) to unravel the heterogeneity of the reproductive and metabolic phenotype of men with KFS by performing a multi-omic analysis in a large cohort at baseline; (ii) to evaluate the efficacy of semaglutide-induced weight loss to achieve metabolic and reproductive benefit in men with Klinefelter syndrome as compared to standard testosterone replacement; (ii) to assess whether addition of hCG to aromatase inhibitors further increases intratesticular testosterone and promotes spermatogenesis in men with KFS.