You control your urges for violence and sex using a tiny tangle of neurons located in a very ancient part of your brain. Now it turns out that this knot of nerves, located in the hypothalamus, can be controlled with a new gene therapy technique that uses flashes of light. What this means is that scientists may be on the verge of turning us into perfect soldiers, unable to stop ourselves from attacking anyone or anything that gets in our way. But this discovery is also the perfect shutdown command for people who can't control their violent urges. Either way you look at it, in ten years, we could be manipulating people's most primal urges with beams of light.
Read A drug that makes you violent, then peaceful again via io9