genetically-modified crops

Genetically modifying crops is a somewhat controversial practice that is nonetheless widespread for a number of reasons (like to try to improve yields, crop hardiness, nutrition, etc.). There is no real evidence that GMO crops are harmful, or have the potential to be harmful (as in there is no known pathway by which they could be harmful) but there are still a number of potential issues with their use:

1. GMO seeds are patented, and farmers are required to pay huge fees every year to massive corporations like Monsanto in order to use them. They cannot (or are not allowed to) use seeds produced by the previous year’s crop; they must rebuy. Furthermore, natural pollinators like bees can pollinate neighbours’ crops with GMO genetics, and then the neighbours can get into legal trouble through no fault of their own.
2. Many GMO crops have been modified to make them herbicide-resistant, so farmers can get away with drowning their crops in herbicides to try to target weeds. These herbicides then leech into the environment, into water supplies, etc. and this is thought to result in bad outcomes down the line
3. The rise of GMOs is bad for the genetic diversity of crops, as their superior yields, hardiness, etc. make them a more attractive option for many farmers and as a result they “crowd out” natural, genetically diverse crops. This implies a dramatic loss of long-term hardiness though, because if vast swathes of crops are all genetically identical, that makes them much more vulnerable to crop diseases than natural crops exhibiting genetic diversity would be.