Data on the effects of recombinant human GH (hGH) therapy during male puberty on future testis function are still inconclusive. The aim of this study was to investigate the long-term effects of recombinant hGH treatment on reproductive function in non-GH-deficient short stature boys. Eight boys with non-GH-deficient short stature, affected by constitutional delay of puberty or idiopathic short stature, were retrospectively studied after recombinant-hGH treatment to verify gonadal development, hormone production and semen quality. Auxological data, endocrinological/ andrological parameters and laboratory evaluation (GH, IGF-I, FSH, LH, testosterone, inhibin B) were assessed before treatment; after completion of pubertal development, the same parameters plus SHBG levels were evaluated and a seminal fluid examination was conducted (ejaculate volume, pH, sperm concentration, total sperm count, forward and total motility, morphology). All patients showed normal testicular volume at the final pubertal stage, with regular androgenization. Hormonal levels were within the normal adult range in all boys. Considering the immature reproductive system of these patients in comparison with adults, semen parameters (sperm count, motility, and morphology) were within almost normal limits, except in one patient. Although patients showed the wide fluctuation of semen values frequently observed at the end of puberty, the hypophysis-gonadal axis hormones were in the normal range in all adolescents. Pathological measurements of some seminal parameters were found in one patient only. This study suggests that recombinant hGH treatment has no detrimental effects on the development and maturation of male gonadal function in non- GH deficient short stature young patients.