Markor, I'm totally flabbergasted by your overall opinion here. I know I'm not going to convince anybody, but let me sum up what I don't get.
You think there are too many people, and apparently you would like to see a bunch of them die off. However, you are extremely concerned that some small subset of that overall population (the ones who shouldn't die off) might develop illness later in life (thus shortening their life).
How are these not contradictory statements?!? Further, how do we decide which people are the right ones to off?
Finally, I think the key insight about GM is that, if successful, it is actually an extremely environmentally friendly solution to the problems we have. If you can grow the same quantity of crops on 1/4 the land, then the rest can lie fallow or even be returned to wildlife. This is a good thing! If we pests love to eat tomatoes but for some reason ignore corn, and we can find out why that is and transplant that gene to the tomatoes, it might mean we don't need to use pesticide. This is also a good thing!