The methodology that raises my concern is incorporation of foreign genomes into organisms that are likely to interbreed with wild populations. Like the Frankensalmon escapees that, suppsoedly sterile, managed to breed with wild salmon.

At first blush it sounds great -- the frankensalmon grow at a phenomenal rate on low quality food and poor living conditions. It maybe good, I dunno. But on the other hand, wild salmon are already under tremendous pressure from a wide variety of factors. Nobody knows how the foreign genes will affect the fitness of the wild population.

Concerning health of GM food sources? I have seen no credible evidence of any direct negative impact to human health.