WASHINGTON (Reuters) - Too much testosterone can kill brain cells, researchers said on Tuesday in a finding that may help explain why steroid abuse can cause behaviorchanges like aggressiveness and suicidal tendencies. [...] Ehrlich's team tried the same thing with the "female" hormone estrogen, just to be fair. "We were surprised, but it actually looks like estrogen is neuroprotective. If anything, there is less cell death in the presence of estrogen," she said. [...] "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," Ehrlich said in a statement.