1) Banning the production of GMO crops is important because contamination is inevitable among all farms including the organic GMO-Free farms. If a GMO farm is producing crops nearby a non-GMO farm, chances are that contamination from a GMO farm will spread, and even though a food is labelled GMO free chances are that food was grown nearby a farm that uses pesticides such as Monsanto's Roundup Ready, or that the seeds have been altered scientifically, therefore making organic farms susceptible to contamination. Insects such as bees that pollinate from weeds such as alfalfa can spread the pollen to other farms. An organic farmer could buy their chicks from hens that have been exposed to GMO feed, anti-biotic, and hormone-based products, making the chicks already weak at birth, and already affecting the quality of meat and eggs.
2) Negative effects on the health of Ontarians: Health Hazards
No Long-Term Safety Testing—Genetic engineering uses material from organisms that have never been part of the human food supply to change the fundamental nature of the food we eat. Without long-term testing no one knows if these foods are safe.
Toxins—Genetic engineering can cause unexpected mutations in an organism, which can create new and higher levels of toxins in foods. (Inose 1995, Mayeno 1994)
Allergic Reactions—Genetic engineering can also produce unforeseen and unknown allergens in foods. (Nordlee 1996)
Decreased Nutritional Value—transgenic foods may mislead consumers with counterfeit freshness. A luscious-looking, bright red genetically engineered tomato could be several weeks old and of little nutritional worth.
Antibiotic Resistant Bacteria—Genetic engineers use antibiotic-resistance genes to mark genetically engineered cells. This means that genetically engineered crops contain genes which confer resistance to antibiotics. These genes may be picked up by bacteria which may infect us. (New Scientist 1999)
Problems Cannot Be Traced—without labels, our public health agencies are powerless to trace problems of any kind back to their source. The potential for tragedy is staggering.
Side Effects can Kill—37 people died, 1500 were partially paralyzed, and 5000 more were temporarily disabled by a syndrome that was finally linked to tryptophan made by genetically-engineered bacteria. (Mayeno 1994)
This is just some information supporting the negative effects of GMO's in terms of health, taken from this website http://www.safe-food.org/-issue/dangers.html if you are interested you may look further into the details of the dangers concerning GMO crops.