I can tell you this: anyone who thinks that artificially shrinking the pool of experts which you can pick to speak at a conference won't affect the quality of the presentations is deluding themselves.
Whether this is true or not, the parent commenter is right - quotas seem to be the direction that Westernized societies are heading for in the 21st century. I remember last year reading that the European Commission put forth a proposal requiring that publicly traded companies must have 40% of their non-executive board posts filled by women by 2020 [1]. Whether that ends up getting approved or not, it seems like a bellwether for how these issues are going to be framed.
[1] http://www.spiegel.de/international/europe/european-commissi...