For example, some experts assert that genetically modifi ed (GM) crops will signifi cantly increase crop yields without requiring any additional farmland, thus preserving valuable rain forests and animal habitats. herbicides, and pesticides. Farmers are not allowed to trade or save GM seed from one harvest to the next, and "terminator technology" (producing grains that are genetically modifi ed so that they cannot be used to generate new crops) is under development. (See http:⁄⁄www.globalissues.org/ EnvIssues/GEFood/Terminator.asp for more information on this technology.) Thus, ethical considerations of distributive justice and benefi cence must be considered in the debate about the global applicability of GM crops.