It could destroy women's sport.The years of focus and debate against Castor Sumenya by other female athletes and the governing body has pretty much lead to her being hounded out of the sport. If men who identify as women expect to compete then I would expect a far bigger backlash from women in those sports. For me it just shouldn’t be allowed and would make a mockery of the sport.
Semenya is a different matter. She has high testosterone levels, may be intersex.