Juicing the Brain in Scientific American

Scientific American reports on military research to "juice up" soldiers' brains using amphetamine-alternatives like Provigil and Ampakine CX717. The aim, of course, is to find the next generation "go pill" that fighters can pop to stay awake longer without impairing their cognitive abilities. The article also discusses transcranial magnetic stimulation (TMS), a method to stimulate specific regions of neurons to possibly alleviate depression or, of interest to the military, improve reaction time. (More on TMS in this Popular Science article I wrote several years ago.) For me though, the most interesting bit in the SciAm article is the brief discussion of the "fear gene." From the article:
A distinguished team of U.S. researchers reported in 2005 that a gene called stathmin, which is expressed in the amygdala (the seat of emotion), is associated with both innate and learned fear. The researchers bred mice without the gene and put them in aversive situations, such as giving them a mild shock at a certain point in their cage. Normal mice exhibited traditional fear behavior by freezing in place, but the altered mice froze less often. And when both types of mice were put in an open field environment--an innately threatening situation--the mice without stathmin spent more time in the center of the field and explored more than the control mice.

Do individuals who have lesser stathmin expression exhibit less fear? It is unlikely that there is a one-to-one correspondence, because humans are far more psychologically complex than mice, capable of modifying their genetically programmed behavior. Yet it is not difficult to imagine that a military official who overestimates the significance of genetic information will someday propose screening Special Forces candidates, or even raw recruits, for the "fear gene." Indeed, a few years ago the Burlington Northern Santa Fe Railway Company had to pay $2.2 million to employees who had been secretly tested for a gene associated with carpal tunnel syndrome, even though the scientists who developed the testing technique said it could not work for that purpose. The company was trying to see if the workers' medical claims were attributable to their jobs or their genes.

If DNA testing for a fear gene is both scientifically and ethically dicey, what about setting out to create people who lack that characteristic? Would breeding humans without stathmin or other genes associated with fear reactions engender more courageous fighters? Would parents sign on for such meddling if they harbored ambitions for a child capable of a glorious military career or just didn't want to give birth to a "sissy"?