its part of the plan of big agri-chemical corps to own our food supply. anyone can plant, harvest, and sell corn and soy beans, etc. but once its been genetically modified, it is now "owned" by the company that holds the patent. once these Genetically-Modified-Organisms crops contaminate all the crops on earth (via cross pollination due to wind and animals and other natural forces), these corporations will sue anyone who plants crops but doensn't pay a liscensing fee.
its part of the urge to control, to possess, and to profit.