This complex interplay between sex hormones and the GH/IGF-I axis has a clinically relevant impact in patients with hypopituitarism and the gender-dimorphic GH secretion pattern must be taken into account both in diagnosis of GH deficiency (GHD) and in detection of the appropriate and effective dose of GH replacement treatment (GHT) to be used (11). The gene discussed is GH1; the disease is hypopituitarism.