http://www.bbc.co.uk/news/world-australia-43044082 Apparently it has been ruled that a transgender woman can play Australian rules football alongside women. You have to wonder how this can be so, given that this person has had the benefit of 25 years of testosterone that her fellow competitors did not have access to. The physiological benefits of this hormone are beyond doubt, this is why testosterone levels are monitored by anti-doping agencies in elite sport, and testosterone doping is banned. Regardless of current levels of testosterone, things like bone density would still have residual benefits. I think this is a crazy decision, and potentially dangerous.