As Australian courts test legal definitions of gender, what will it mean for sex discrimination laws?

The judge in Roxanne Tickle’s case found sex is changeable and also went a step further, finding that how a person identifies and is recognised socially is enough to access gender identity protections. Photograph: Dean Lewins/AAP

For more than a decade, it has been illegal to discriminate in Australia on the basis of gender.

Now a series of cases at the federal level are testing that principle – and raising questions about what it means to be a woman.