Bad effects of ignoring biology? Carroll mentioned the typing of depressed people as malingerers. How about New age crap about negative emotions causing cancer, and positive attitudes curing it? The whole alternative medicine field is full of untested, fanciful, sometimes dangerous notions--and the only people interested in testing these treatments scientifically are scientists. The gurus are perfectly happy to use (or make up) anecdotal evidence. What about health fads, weird diet fads, Gary Null type health cults. A little hard science would save people billions of dollars, and maybe some lives too. One might also mention christian Science and other faith cults, which has resulted in lots of deaths of children whose parents think they can be healed by prayer alone. And then there's Creationism! and indeed religion generally -- are not such concepts as the resurrection of the body and reincarnation rather spectacular examples of the ignoring of biology?
I would also cite the discourse around AIDS as a case in which "biology" (HIV is a virus) tends to represent the humane, less judgmental, less stigmatizing and more realistic approach. It is a biological argument to assert that "being gay" or 'being promiscuous" doesn't cause AIDS, that AIDS is not the property of a partiuclar group of people (gays, haitians, drug addicts etc), a punishment for sin, etc.
I don't think you can argue that the problem in modern America is that too many people have a scientific worldview! Or know too much biology.
Katha