I believe they have the potential to be harmful, as they are artificial. Even if they were actually safe, we have not conducted enough testing to be sure. GMOs could also cause a lot of biological problems, such as resistance (similar to how bacteria can develop antibiotic resistance), unfamiliar genetic material replicating to become weeds, a less diverse crop yield, and other unknown issues in the environment.
GMOs are not harmful/not as harmful as people say33.33%
GMOs are dangerous and should be avoided66.67%