Change in body weight and composition caused by gonadectomy and testosterone treatment. (A) XYY mice gained more weight than XY (F(1,46) = 4.58, p = 0.038, main effect). In addition, the change in body weight in males vs. females depended on sex chromosome complement when comparing XY with XX (F(1,53) = 0.020, p = 0.02, *INT) and XY with XXY (F(1,51) = 5.42, p = 0.024, *INT). (B) Gonadal females overall lost more relative fat mass than gonadal males (F(1,84) = 4.37, p = 0.039), but there was no significant effect of sex chromosome complement. (C) Gonadal females overall gained more relative lean mass than gonadal males (F(1,84) = 13.82, p = 0.0004). The difference between XY and XX was different depending on their gonadal sex (F(1,53) = 9.56, p = 0.003, *INT). *INT indicates significant interactions of gonadal sex and sex chromosome complement. Values are mean ± SEM.