We often hear about the effects, positive and negative, of testosterone. This "male" hormone (in scare quotes because both men's and women's bodies produce both estrogen and testosterone) is credited with enhanced libido, energy, and immune function and blamed for violent or antisocial behavior and baldness.

Testosterone is also the subject of a Yale School of Medicine finding, reported CNN: Too much testosterone kills brain cells.

I was interested to read this, and, I'll admit, I found my bias toward thinking that the natural system has it pretty well figured out was supported by Barbara Ehrlich's statement "Too little testosterone is bad, too much is bad but the right amount is perfect." It's not a deep observation, but it is satisfying.

Satisfying, that is, until I got to a later statement from Ehrlich, which sounds yawn-inducingly like yet another biological excuse for boys to be boys: "Next time a muscle-bound guy in a sports car cuts you off on the highway, don't get mad -- just take a deep breath and realize that it might not be his fault."

It may be satisfying to stereotype all muscular men as cavemen, and to blame bad behavior on hormones rather than plain old bad manners, but it sure isn't scientific.