That's done in only two sports. Do you know what they are? Answer later. In most sports there are physical differences that preclude competing evenly. For example, most adult women can't keep up with men in swimming races because of their built-in drag. And sometimes, there is a difference in terms of viewer interest. How much interest would be in watching two men mud-wrestle? Oh, BTW, the two sports in which men and women compete together are yachting and equestrian. In these, the greater upper-body strength of men is not a factor. Obviously, I am excluding such sports as mixed-doubles tennis or the amateur sports pitting the different departments of a business against one another at the company picnic. You'd think that there would be other sports where the two sexes could compete evenly. Darts, maybe?