Throughout the history of life on Earth, which spans 3.6 billion years, natural selection has acted on genetic variance to select traits that favor survival; this process has been vital to the evolution and diversification of life. Until recently, genetic variance had resulted from gene mutations, chromosome duplication errors and genetic recombination related to sexual reproduction. When humans learned to domesticate animals and cultivate crops, some 10,000 years ago, we began to take an active role in selecting traits that we deemed to be favorable; though we did not understand the science of genetics until very recently, humans were having a significant impact on the diversity and relative populations of life on Earth.
Over the last few decades, we have learned to alter genes in plants and animals (including humans) in order to treat disease, restore physiologic function and improve the productivity of various species. In the case of crops, man has engineered plants that resist drought, are less susceptible to infestations and produce a higher yield on less land. This ability has become especially valuable in meeting global food demand while placing less stress on natural habitats and reducing dependence on pesticides and herbicides. My personal research has failed to turn up convincing evidence of harm to humans or to the natural environment related to the genetic engineering of crops. On the other hand, I have substantial concerns related to the use of hormones and other supplements in the raising of livestock.
As we face global warming and potential mass starvation across the globe, we need to address both human overpopulation and the sustainable production of food that is safe for consumption and safe for the environment. Modern science has and will continue to be part of the solution; those who oppose genetic engineering, which will surely play an increasing role in medicine, agriculture, biofuel production and other vital fields, must offer clear, scientific evidence of harm in order to derail that progress. Mysticism and zealotry are neither sufficient nor acceptable.