Many serious people are projecting that within ten to fifteen years we'll be able to start on a significant program of cognitive enhancement. To craft drugs, hormone cocktails, neurointerfaces, and neuroprotheses that will significantly make their users smarter and more capable, initially to a degree perhaps comparable to the invention of literacy or science, but soon far outstripping any previous transition in the history of the human mind.
If we grant that this is possible, the only real debate is when. 10 years? 15? 50? 100? The gears of capitalism and human nature ensure that it'll come, sooner or later. And I think the only way this won't end in certain disaster is to develop, formalize, and enforce a new social contract regarding human enhancement.
My suggestion? If you want to use biotechnology to make yourself smarter, you also have to use it to make yourself nicer.
If we don't make this the accepted contract, I fear we'll ping-pong between two unpalatable scenarios: either open things up to an enhancement free-for-all (and there's likely a strong correlation between people who most want to be cognitively enhanced and people for whom it's not in society's best interests to grant a competitive advantage), or criminalize enhancement (and if we outlaw enhancement, only outlaws will be enhanced).