Macdonald once famously said, "I feel that one of the basic requirements of being a sprinter is having legs." If we apply that same logic to the transgender/intersex debate, then we'd have an easy solution. "I feel that a basic requirement of being eligible to compete in elite women's sport is to never have had functioning testes."
*MB: RIP Norm Macdonald: How Macdonald's Simple-Truth Logic Could Help Solve the Transgender/Intersex Crisis In Women's Sports