Genesis, Jacob asks his father-in-law, Laban, to compensate him for 14 years of unpaid labor. His request is strange: all the speckled and spotted goats and all the dark sheep from Laban's flock--the least desirable animals. Jacob then peels back the bark of tree branches, making stripes, and places these rods in the animals' water troughs. According to the story, the sight of the rods make the animals mate, and soon, Jacob's flock is more robust than Laban's. Jacob may not have known it, but genes were behind this success: By selectively mating the animals, he brought out genes that would produce desirable traits.
This tale is the first time Jews weighed in on the issue of genetic manipulation, but millennia later, the issue is still a topic of debate. Today, the discussion focuses not on breeding, but on genetically modified organisms, or GM0s, plants and animals whose DNA has been explicitly altered by humans. Genetic engineering is a more high-tech way to bring out specific traits; scientists can now add, delete or adjust genetic material by using "gene guns" to shoot microscopic bullets coated with DNA into living cells. This tactic allows vastly different species that could not breed in nature--including those from the animal and plant kingdoms--to mix genetic material.
The first genetically modified foods to go on the market in the 1980s were typically crops designed by chemical companies to resist herbicides and pesticides. Now the U.S. Department of Agriculture says that the majority of America's corn and soybeans--primary ingredients in most processed foods, from breakfast cereal to soda, as well as in animal feed--are genetically modified. Some researchers estimate that 70 percent of all processed foods contain some genetically modified ingredients.
Since food is a matter of law and ethics in Judaism, these laboratory creations raise an important question: are genetically modified foods permissible? One aspect of this is whether they are kosher. Because many genetically modified foods are trans-genic--or contain the DNA of another organism--fears have arisen that the DNA of pigs may be implanted into otherwise acceptable foods. Does the addition of pig DNA make an organism treit?
The Orthodox Union has a simple answer: Genetically modified foods are kosher. Its reasoning is that the laws of kashrut do not operate on a molecular level; pig DNA is too small to alter a food's legal status. The Conservative movement's Committee on Jewish Law and Standards of the Rabbinical Assembly also defends the kosher label of genetically modified food, and draws an analogy to organ transplants. Under Jewish law, transplanted organs that function properly become part of the host. As with a pig's heart valve that is inserted into a human body, the pig's DNA loses its "pigness" once it successfully enters a new organism.
Another potential dilemma is combining the DNA of different organisms. While the Bible does not mention genetic modification explicitly, the books of Leviticus and Deuteronomy prohibit kilayim, or forbidden mixtures, particularly in agriculture. In Leviticus, God instructs: "You shall not let your cattle mate with a different kind; you shall not sow your field with two kinds of seed; you shall not put on cloth from a mixture of two different kinds of material." The reasoning behind this verse, writes 13th-century scholar Nahmanides, is to protect the species that God created, as well as their ability to procreate.
Some have interpreted these passages as a ban on genetic modification, but Michael Broyde, an Orthodox rabbi and senior fellow at the Center for the Study of Law and Religion at Emory University, says the laws of kilayim are not meant to be applied broadly. …