Concerns have been raised about the wisdom and safety of genetically modifying crops and other organisms. These concerns are centered on three claims:

Advocates of biotechnology tend to agree with the first claim. However, they point out that all crops are unnatural in the sense that they come from artificially bred plants growing in a manipulated environment (a farmer’s field). Recombinant DNA technology just adds another level of sophistication to these technologies. Synthetic biology, however, takes genetic manipulation dramatically further.

To counter concern about whether genetically engineered crops are safe for human consumption, biotechnology advocates point out that only single genes are added and that these genes are specific for plant function. For example, the B. thuringiensis toxin produced by transgenic plants has no effect on people. However, as plant biotechnology moves from adding genes that improve plant growth to adding genes that affect human biology, such concerns will become more pressing.

Various negative environmental impacts have been envisaged. The concern has been raised, for example, about the possible “escape” of transgenes from crops to other species. If the gene for herbicide resistance, for example, were inadvertently transferred from a crop plant to a closely related weed, that weed could thrive in herbicide-treated areas. Increased use of herbicides has already resulted in the selection of weeds with naturally occurring mutations that make them resistant to that herbicide. Widespread use of glyphosate on fields of glyphosate-resistant crops, for example, has resulted in the selection of rare mutations in weeds that make them resistant to glyphosate. Field-evolved resistance now occurs in half the major weed species examined.

Because of the potential benefits of biotechnology, scientists believe that it is wise to proceed, albeit with caution.