Monsanto Co., the world's largest seed company, and its brethren of global biotech crop developers are spreading the word that as far as the safety of their genetically modified grain goes, the science is solidly on their side. The message of "settled" science has become the rallying cry for defenders of the crops and food commonly referred to as GMOs as they push back against consumers, environmentalists, lawmakers and others who want the crops labeled, restricted or banned.