Transgenic plants include genes from other organisms that make them resistant to glyphosate or toxic to insects. A. Proponents of transgenic plants argue that they reduce the use of harmful pesticides and allow the use of more environmentally friendly herbicides. B. Opponents of transgenic plants worry that resistance to glyphosate may spread to weeds and that resistance to Bt toxin may develop among insect pests. C. Use of transgenic plants may lead farmers to neglect more sustainable agricultural practices, and may also cause harm to nontarget organisms. D. One argument against Bt plants is that some of the most harmful pests are not Bt susceptible, making application of supplementary pesticides necessary. E. Over the long term, transgenic plants are likely to lose their glyphosate resistance through evolution and hybridization with nonresistant relatives. F. Many of the problems identified with transgenic plants today will likely disappear as scientists design transgenic plants that are more ecologically friendly.