Genetically modified foods are crops where genes from bacteria or viruses are forced into their DNA. The two main categories are those that are engineered not to die when sprayed with a toxic herbicide and those that produce their own toxic insecticide.
We don't have long-term data yet for either humans or animals, so basically, we're playing with a potential time bomb.
What kids eat really matters. GMOs are pervasive in processed foods, so eliminating them from the diet can go a long way toward helping you avoid feeding GMOs to yourself or your family.