I've been very clear that I'm a layman, such as certainly most of the commenters here. I qualified using "AFAIK" and I've heard this on different occasions by people who have actual experience in the field. You can find similar claims on this page, partly backed by links. For example, I too have heard about studies evidencing that gender differences are more stark in developed countries with well functioning social systems, where people are freeer to choose their profession based on personal interest rather than for example economic aspects.