Concerns about negative consequences from gene flow between genetically engineered organisms and wild populations are valid. Most corn and soybean crops grown in the midwestern USA are genetically modified. There are corn and soybean varieties that are resistant to herbicides like glyphosate and corn that produces neonicotinoid pesticide within all of its tissues. These genetic modifications are meant to increase yields of crops but there is little evidence that yields actually increase. While scientists are concerned genetically engineered organisms can have negative effects on surrounding plant and animal communities, the risk of gene flow between genetically engineered organisms and wild populations is yet another concern. Many farmed crops may be weed resistant and reproduce with wild relatives. More research is necessary to understand how much gene flow between genetically engineered crops and wild populations occurs, and the impacts of genetic mixing.