The authors quantify the economic impact of introducing genetically modified (GM) crops in the research paper from Iowa State University. Short-run results suggest that it might be optimal to maintain the identity of a greater proportion of non-GM grain than is currently demanded by non-GM consumers. Long-run results show that GM crops almost always benefit society, but one scenario is presented where overall welfare falls.
Link
http://www.agbioforum.org/v5n3/v5n3a02-lence.htm