A uniform measure of the gender-related differential performance of female and male Olympic and World champions is proposed: relative power output applied to the environment. Laws of physics are employed to derive equations for estimating relative power output. In previous controlled laboratory studies, equally trained male and female athletes were shown to have a relative power output not significantly different from relative lean body mass. As to the estimated power output for 32 Olympic and World championship events contested between 1976 and 2004, eight in running, four in speed skating, three in jumping, twelve in swimming and five in rowing: 100% of the 32 event mean percentage differences in power output and 96% of the 411 event percentage differences in power output are within one standard deviation of the appropriate lean body mass percentage difference, consistent with equality of training. For 1952-1972, significantly higher percentage differences in power output are estimated in running and swimming compared with 1976-2004, consistent with women being less well trained than men during that earlier period. It is noted that efforts in recent years to provide equality of opportunity for female athletes coincide with equalization of estimated relative power output in competition with the relative lean body mass.