Trans women's participation in sport is an election issue. This is what the science says

If you've been following the federal election campaign, you'd be forgiven for thinking trans women's participation in sport is the biggest issue facing the nation.

Over the past week, Prime Minister Scott Morrison and his controversial «captain's pick» for Warringah, Katherine Deves, have been drawn into an increasingly ugly debate about a private member's bill by Liberal senator Claire Chandler which seeks to ban transwomen from participating in women's sport by refusing to recognise them as women.

Deves, in particular, has been rebuked for a range of extremist comments, including video that has surfaced of her likening her lobbying on the issue to standing up against the Holocaust.

Although Morrison has said the Coalition «does not have any plans» to sponsor such a bill, he has previously labelled it «terrific» and said he shares Deves's and Chandler's views on trans participation in sport.

But while those who believe trans women should be excluded from sport have defended their right to «free speech», little airtime has been given to examining the science behind the claims being made.

So what does the science say about trans women and sport?

Ada Cheung is a principal research fellow in endocrinology at Austin Health and leads the Trans Health Research program in partnership with the University of Melbourne.

She says medical transitions have a range of complicated impacts on the body which throw into doubt claims about trans women having a «biological advantage» in sport.

Trans women, she says, will often start taking a form of estrogen as well as testosterone blockers to increase their estrogen and decrease their testosterone levels to a more «typical female range».

«When they do that, they get physical changes to their muscle