Earlier quoted context omitted.
If you think about it, a 55/56 ratio (.98) is only commensurate with a distribution of mathematical talent by which the vast majority of women can't add 2 and 2 together. Like, it would not even justified by women being "somewhat" less good at maths at the high level than men. Women would have to be really, really bad at maths for that to be a natural result.
No, they just have to be vastly less likely to be top 0.001% at math. In any activity where you can distinguish the top 0.001% talents versus the top 0.01%, you're going to get way fewer women at the top. One of the reasons is, half their cells are using one X chromosome and half are using the other, so they're more likely to get their performance dragged down by deleterious mutations.
This statement is wrong 2x.
1. Lyonization is a process of inactivation that happens early in embryotic development so only one X is dominant in all somatic cells.
2. The chromatin packed X is not completely inactive, so if the dominant X has a deleterious variant the other X can sometime confer protection. Without a good copy of an X allele men getting X-linked disorder is a foregone conclusion. Women on the other hand suffer from X-linked disorders approximately 50-25% as often.
Also there is no evidence linking any of this to math ability