Using simple high-school maths, it is demonstrated that any regulation intended to “protect” single-sex spaces from trans women will have the exact opposite effect because cis women will be disproportionately afflicted by it.

The research question that we wish to answer is the following: what is the proportion of women with shoe size greater or equal to UK size 9? We want to know how unusual this is. Is it more or less unusual than the proportion of trans people in the general population?