Normally, the arguments against genetically modified organisms (GMOs) centres around the notion that we should not combine the genes of species that could never occur naturally (at least, this is one of Joel Salatin's main counterpoints). Well, today there is another reason: conventional wisdom, meet genetic engineering.
In a story reported today in the Edmonton Journal, scientists have apparently modified a sheep such that it produces an over-abundance of supposedly "heart healthy" polyunsaturated fat (PUFAs). This "breakthrough" is ironic, since PUFAs are thought by many to be one of the main causes of modern health issues. Non-GMO sheep, and their saturated fat (that is healthy, by the way) are just fine, thank you, especially when they are raised from start to finish on grass, the way nature intended.
If you needed ammunition to win an argument against GMOs, this is a good one.