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characteristics. Also, these traits or characteristics, such as height, hair, or eye color, may be modified or changed by genetic engineering. For instance, physicians will some day alter genes for height in preimplantation embryos or fetuses. They may seek to change complex human traits, intelligence or personality, each of which is coded by a large number of genes. This means that parents will be able to begin to design their own babies, replacing genes already there for what they regard as undesirable traits, adding genes not there for what they regard as desirable traits, and altering, to some degree, personality and intelligence. Genetic enhancement will increase their children’s opportunities for a long, healthy life, marked by happiness and success.
For purposes of the discussion that follows, I will assume that genetic enhancement is safe and effective. This is not to deny the possibility of deleterious side effects or unanticipated long-term negative consequences that may show up years later, even after rigorous animal testing, but one expert predicts,“No matter what technique, or techniques, are ultimately used, genetic engineering of human embryos is sure to become feasible, safe, and efficient by the middle of the twenty-first century.”
The Jewish tradition remains divided on nontherapeutic gene manipulation, with the likelihood that most progressive authorities will reach a negative conclusion. Nearly three decades ago, Azriel Rosenfeld , an Orthodox rabbi , supported the use of genetic techniques to enhance humans. Rabbi Rosenfeld noted:
Our sages recognize, and perhaps even encourage, the use of prenatal(or better, preconceptual) influences to improve one's offspring:Rabbi Yohanan(B. Ber. 20a, B. B. M. 84a) used to go and sit at the gates of the