Types of GMOs
The Bt-toxin produced in GMO crops is intentionally altered to be more immediately toxic than the spray form. It is also produced in crops at a concentration that is thousands of times that which is used in natural sprays. And whereas natural sprays wash off in the rain and biodegrade in sunlight, the Bt-toxin in crops remains encapsulated.
The biotech industry claims that Bt crops can reduce the need for applications of chemical insecticide by farmers. Research on GMO corn and cotton have shown that in the first few seasons this can be true. But due to the presence of new non-target insects that are not susceptible to Bt-toxin, and due also to the increased tolerance among the target insects, farmers often end up spraying more chemical insecticide on Bt crops than the non-GMO crops.
Furthermore, even when there is a reduction of chemical sprays in the initial seasons, the amount of Bt-toxin produced in the field by the crops adds up to far more insecticide per acre than the amount of chemical spray displaced. The disparity is even greater when you add the neonicotinoid insecticide seed treatments added to most GMO seeds.
Numerous studies on Bt crops demonstrate significant harm to the environment.
The three types of Bt crops currently commercialized are corn, cotton and, in South America, soy. Bt eggplant is being grown in Bangladesh. 
Unfortunately, Roundup’s chief poison glyphosate is absorbed into the plant and ends up in the food we eat. There are numerous studies showing significant health damage linked to even tiny amounts of glyphosate and Roundup.
Roundup also damages the environment, according to a large number of studies.
The herbicide tolerant crops have also increased the use of the associated herbicide. First, farmers spray over the entire field instead of spot spraying. Second, weeds have developed tolerance to the weed killer, resulting in farmers using more concentrated mixtures and spraying more and more times during the growing season.
Herbicide tolerant crops currently on the market include soy, corn, cotton, canola, sugar beets, and alfalfa. 
GENOME EDITING (GENE EDITING):
The biotech industry has initiated a global campaign to convince regulators and the public that gene editing is so safe and predictable, no regulation or government oversight is needed. Nonetheless, there is now overwhelming evidence that the technology does consistently create unpredictable side effects that can be dangerous to health and the environment. 
In the 1980s, a Japanese corporation used GMO bacteria to create a health supplement L-tryptophan that killed about 100 Americans and caused 5,000-10,000 to fall sick or become permanently disabled.
Other food products on the market that are produced with GMO bacteria or yeast include aspartame, Impossible Burger, and vanilla. Recombinant bovine growth hormone (rBGH) is also produced using this method. 
GENE SILENCING OR RNAI:
Numerous scientists, including some who worked at the USDA and EPA, have expressed concern because research suggests that the RNA mechanism can alter “non-target” organisms. In other words, plant pests, animals, and even humans that consume these GMOs may experience altered gene expression. Unfortunately, no research has been conducted on the GMO apples and potatoes to rule this out. 
We would like to recommend GMO Myths and truths. In particular, we recommend the following sections: GMO vs traditional breeding, feed the world, Increases yield, Decrease pesticide use.
Download a PDF of the full GMO Myths and Truths report here.
- Smith, Jeffrey M. (2007). Genetic Roulette: The Documented Health Risks of Genetically Engineered Foods. Yes! Books.
- What is genome editing? Retrieved from https://www.genome.gov/about-genomics/policy-issues/what-is-Genome-Editing
- What is Synthetic Biology? Retrieved form https://www.synbioproject.org/topics/synbio101/definition/
- (2013). How RNAi Works. Retrieved from https://www.umassmed.edu/rti/biology/how-rnai-works/