Why aren’t we acting on the evidence of what works for gender equality?

Two things are being conflated here: perceptions of gender bias (internal or external) in the choice of subjects to study and the threat of inappropriate behaviour from supervisors. Not helpful, even though both are issues to be dealt with if we want people to pursue all areas of study irrespective of what their gender happens to be. I'm actually more bothered by the (mis)perception that "Maths is hard" than any thoughts that it might be harder for girls than for boys. If it's hard, it's because people are believing that it is and divert their efforts to other areas where they feel their efforts will be rewarded and because it by and large isn't very well taught, especially in primary schools. Lacking a basic grounding and the belief that those numbers will do your bidding, maths will be hard as you progress through secondary school and pick options. When I was at school I did physics A-level but not maths (too busy learning biology and chemistry!). My school made the 5 of us in that situation - physics but not maths - take an hour a week of maths so that we could follow the more mathematical bits of physics. Those Wednesday afternoons were a high spot of the week! Looking back it was "maths without pressure" - there was no test, nothing abstract, all relevant to other stuff we were learning. Workplace harassment is a quite different matter: obviously abhorrent and needs dealing with. But it's unlikely to affect subject choice or retention: there are obnoxious and abusive individuals in all disciplines.