I saw one suggestion which was to so away with male and female competitions, and instead have "open" and "restricted" comps. Open would be available to anyone, male or female, while you could set up as many restricted comps as you needed for the particular sport or activity with whatever rules make sense. So the 100m sprint might have Open, Restricted - Testosterone, and Restricted - Height - with whatever T level or height in centimetres decided by the relevant authority. Whereas something like weightlifting might have Restricted - Weight as it's own class. The idea being any gender can compete provided provided meet the restrictions in place to make an interesting/fair competition within that bracket.