There has been a wave of concerns about the negative impacts of genetically modified crops, or GM crops, on human health and the environment. The possibility that these crops could harm human health comes from several ideas. One is that the use of antibiotic marker genes could increase bacterial resistance to antibiotics. Another concern is that the new proteins in GM crops could lead to allergic reactions in humans. A third concern is that the introduction of a new gene combination into the environment could have long-term negative implications. Concerns regarding the environmental impact of GM crops may stem from the idea that genetically engineered insect-resistant crops may cause harm to many more insect species than the ones targeted. A second worry is that farmers might end up using more herbicides and thus harm wildlife. Further, there is also the possibility that the genes from GM crops could spread to wild plants—imagine herbicide- and insect-resistant weeds.

Underlying both these areas of concern is the idea that GM plants are 'unnatural'. That is a simplistic assumption. Very little modern food is natural. Conventional breeding methods have caused major genetic changes. For example, traditional plant breeding involves selecting the strong individuals and then transferring the pollen of a male superior plant to a female superior plant—it is hard to say that this is 'natural'. Furthermore, a 2002 review of GM science revealed that the risk is low. Nevertheless, the negativity that surrounds GM crops could majorly impact the demand for GM food, at least in the short term.