Because gene therapy involves making changes to the body’s basic building blocks (DNA), it raises many unique ethical concerns. The ethical questions surrounding gene therapy and genome editing include:

• How can “good” and “bad” uses of these technologies be distinguished?

• Who decides which traits are normal and which constitute a disability or disorder?

• Will the high costs of gene therapy make it available only to the wealthy?

• Could the widespread use of gene therapy make society less accepting of people who are different?

• Should people be allowed to use gene therapy to enhance basic human traits such as height, intelligence, or athletic ability?

Current research on gene therapy treatment has focused on targeting body (somatic) cells such as bone marrow or blood cells. This type of genetic alteration cannot be passed to a person’s children. Gene therapy could be targeted to egg and sperm cells (germ cells), however, which would allow the genetic changes to be passed to future generations. This approach is known as germline gene therapy.

The idea of these germline alterations is controversial. While it could spare future generations in a family from having a particular genetic disorder, it might affect the development of a fetus in unexpected ways or have long-term side effects that are not yet known. Because people who would be affected by germline gene therapy are not yet born, they can’t choose whether to have the treatment. Because of these ethical concerns, the U.S. Government does not allow federal funds to be used for research on germline gene therapy in people.