Organic and conventional farmers find themselves on opposite sides of the fence as the Legislature considers a bill to make manufacturers of genetically modified seeds liable for damages if their products spread to other crops. Some supporters of the bill, sponsored by Rep. James Schatz, D-Blue Hill, said it would protect farmers’ ability to control what they grow, whether they use organic or conventional methods. Opponents said the bill could cause some manufacturers to remove their products from Maine, depriving conventional farmers of tools they use.