Well it could suggest that the environment has a greater degree of control over the outcome of one's personality than biology.
Edit: Or at least its (the person's personality) manifestations.
I dunno. I remember reading, according to the "average" that the United States had an unusually high proportion of Ts to Fs -- instead of a "normal" proportion of 60%F to 40%T, it was closer to 50-50 (though there were still more female Fs than Ts, there were more Ts than "average"). However, because I have no idea how these statistics were calculated and who were in the sample, this is probably meaningless.
-Carefully taking sips from the Fire Hose of Knowledge