Among the first results Mr Google gave me for USA congress:

Vern Ehlers (R-MI), first elected in 1993
Ph.D. in nuclear physics from UC Berkeley; former chair of the Physics Department at Calvin College in Grand Rapids, MI.

Rush Holt (D-NJ), first elected in 1998
Ph.D in physics from NYU; assistant director of the Princeton Plasma Physics Lab 1989-1998.

Nancy Boyda (D-KS), first elected in 2006
Chemistry/Education double major in college, then worked as analytical chemist and field inspector for the EPA.

John Olver (MA-01), first elected in 1991
Ph.D. in chemistry from MIT; professor of chemistry at several universities, including MIT and UMass-Amherst.

I was actually looking for a list I had seen a few weeks ago, that listed about 20 legislators with heavy science training, such as medical doctors possess. I know where the list is, I just can't get to it right now.

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