Women and men are equally bad at math. Specially at teaching math. It's not an easy subject and it's not a natural way to think about anything.
In my experience this is nonsense. I agree that maths is pretty universally badly taught - after all, if you're good at maths, your career choices are being a quant paid in millions, an engineer or computer scientist paid in hundreds of thousands, or a school teacher paid in a few tens of thousands. The market (and we know that the market is never wrong, don't we, children?) systematically selects people who are bad at maths to teach maths. The results are not surprising.
But maths isn't hard. Maths is very, very easy; it is a natural way to think about more or less everything. If you take the school teachers out of the way and let children get on and learn the physics of whatever it is that interests them (for me it was sailing boats, but it really doesn't matter - we live in a mathematical universe) from the books in their own time, they will be good at maths. I really don't believe anyone is born bad at maths; we're taught to be bad at maths.