Of course genetically modified foods need proper testing, but then, their mere existence causes some people to have a knee-jerk, no-nothing, don't-want-to-know-nothing reaction. "Of course it's bad," they'll say. And...on what grounds? We humans have been monkeying with the genetics of every species we meet since we started crossbreeding crops for better yields, breeding canines for traits we like, and exterminating species that just didn't like us much. The main difference is now we have better tools for the job, and with increased ability to do that job comes increased potential to royally screw the pooch.
A huge success early in GMO work came in India in the 1960's. Obligatory Wiki link: http://en.wikipedia.org/wiki/Green_Revolution
The short version is that the individuals responsible for the introduction of genetically modified rice into Asia in the 1960's are credited with saving approximately, oh, say, -ALL OF INDIA- from famine. And the Philippines. And, come to think of it, most of Asia.
So the option was famine -or- GMO rice. And people chose GMO rice. So if you're willing to condemn the introduction of GMO crops, you must ipso facto state you prefer that on the order of one billion people suffer famine. No two ways about it; the world is what it is. No IR modified rice strains and people starve. Incidentally, poor people in the third word; most of us in the first world have more than sufficient arable land and technology to do without.
So, yes, GMOs need careful testing and management, of course. But let's balance the, "Boo, science!" with the cold, hard truth that human beings are starving, the native crops are not sufficient to feed the populations, and crossbreeding, fertilizers, and outright manipulation of organisms is how human beings have managed to keep themselves fed ever since the first farms. It's also saved countless lives just in the past century.