I've seen no calls to increase the numbers of conservatives/Republicans in STEM, despite the fact that political ideology and affiliation is actually testing the way people think. For example, though the percentage of scientists who lean Rep. is 12% to the general public's 35%, the percentages are 81% and 52% for lean Dem.[1] And the gap in other political values is high as well.

Demographics are only slightly correlated with how people think, so this form of argument falls flat unless you think encouraging conservatives to get into science is far more important.

[1] http://www.people-press.org/2009/07/09/section-4-scientists-...