Here comes the science:
The undergrads were significantly better at guessing than would be expected by chance, and they were especially accurate with women. The likely reason, according to the study: Republican women are more likely than Democratic ones to have stereotypically feminine facial features.
In another experiment, Carpinella and Johnson used a computer program to measure how “sex-typical” the faces of male and female Representatives were, looking at characteristics like jaw shape, lip fullness, and cheekbone placement (they discounted things like hair, makeup, and jewelry). They found that Republican women were more likely to have stereotypically feminine faces — and the effect was more pronounced the more conservative their voting records were. The reverse was true for Democrats — the more liberal their voting records, the less traditionally feminine their faces. The study authors call this “the Michele Bachmann effect.”
I call it, “Obvious.”