DANIEL SAREWITZ devotes an entire column in Slate to the fact that only 6% of scientists self-identify as Republicans (55% self-identify as Democrats) without offering even a hypothetical explanation of how this situation might have come about. This is as close as he gets:

It doesn't seem plausible that the dearth of Republican scientists has the same causes as the under-representation of women or minorities in science. I doubt that teachers are telling young Republicans that math is too hard for them, as they sometimes do with girls; or that socioeconomic factors are making it difficult for Republican students to succeed in science, as is the case for some ethnic minority groups. The idea of mentorship programs for Republican science students, or scholarship programs to attract Republican students to scientific fields, seems laughable, if delightfully ironic. Yet there is clearly something going on that is as yet barely acknowledged, let alone understood. As a first step, leaders of the scientific community should be willing to investigate and discuss the issue.

I can think of three testable hypotheses they might look into. The first is that scientists are hostile towards Republicans, which scares young Republicans away from careers in science. The second is that Republicans are hostile towards science, and don't want to go into careers in science. The third is that young people who go into the sciences tend to end up becoming Democrats, due to factors inherent in the practice of science or to peer-group identification with other scientists. In the absence of data, I leave it to you to decide which you find most plausible. But by all means, social scientists should look into this.