Girls who desire to compete on boys' teams should be permitted to do so if they have the size, strength and skill to match up to the boys they are playing with and against and can therefore to do so safely. Physiological differences within the sexes are greater than the differences between the sexes. Thus, especially in sport leagues below the professional sports level, there will be some individual girls who are able to compete with and against boys, despite the physiological advantages of most boys. Especially in cases where the opportunity to compete on girls' teams is not present, girls with comparable size, strength and skill as the boys they play with and against should be allowed the opportunity to play.