Once a person has passed through male puberty, their body is changed physiologically, resulting in greater muscle mass. The result is a physical advantage for the individual in competitions with others who have passed through female puberty. Allowing individuals with a physiological advantage, who identify as female, to compete in female designated classes introduces an inherently unfair physical advantage. Conducting separate male and female athletic programs, the standard structure for decades, has been done because there is a physiological strength difference between the sexes.