Designer babies is a term that refers to children who develop from embryos that are selected or genetically modified in vitro (outside of the human body, usually in a laboratory setting) to ensure that the resulting children possess certain desired characteristics or traits. One reason the genetic material of embryos might be altered is to correct inherited defects. Some prospective parents who carry genes associated with inherited diseases, for instance, use genetic screening to select embryos without genetic defects in order to avoid passing the condition down to their children. In the future, an experimental technique known as gene therapy may be used to correct faulty genes in vitro and prevent the appearance of genetic diseases or disorders later in life.
A second, more controversial reason the genetic material of embryos might be altered is to enhance or optimize specific traits, such as intelligence or athleticism. Some prospective parents select embryos based on factors that are not related to the child’s health, such as a preference for a certain gender or eye color. Researchers believe that a technique known as genetic enhancement could potentially be used to design babies with attributes or capabilities that exceed the normal range of human function. The idea of using genetic modification to create designer babies has generated a great deal of debate. Supporters assert that it holds the promise to increase human potential, eliminate disease and disability, and improve the quality of life. Critics, on the other hand, argue that it interferes with natural biological processes, creates unfair advantages for genetically enhanced individuals, and involves unforeseen risks.
Methods and Uses of Genetic Screening
The genetic interventions that are involved in the creation of designer babies are performed during in vitro fertilization (IVF), an assisted reproduction procedure in which human eggs are removed from a woman’s ovary and fertilized with a man’s sperm in a laboratory to form embryos. One or more of the embryos are typically selected for transfer to the woman’s uterus, where it is hoped they will implant, develop through pregnancy, and result in a live birth. Spare embryos may be preserved for future use, donated, or discarded. Since it was first performed successfully in 1977, IVF has become a standard medical treatment for infertility that has helped millions of people around the world have children despite an inability to conceive naturally.
The IVF process makes it possible to assess the genetic characteristics of embryos in the laboratory prior to implantation. One reproductive technology used to screen embryos, preimplantation genetic diagnosis (PGD), involves extracting a cell from an IVF embryo to test for specific genetic defects that increase the risk of developing certain inherited diseases, such as cystic fibrosis, hemophilia, sickle-cell anemia, or Tay-Sachs disease. Prospective parents who carry the genes associated with these conditions may use PGD to identify and select embryos without a genetic predisposition in order to avoid passing the disease on to future generations.
A similar procedure known as preimplantation genetic screening (PGS) involves testing the entire genome of an IVF embryo for chromosomal abnormalities, which are associated with Down syndrome and other developmental problems. Rather than looking for a specific disease-causing gene, PGS evaluates the health of the embryo in a more general way. Because the risk of chromosomal abnormalities increases with advanced maternal reproductive age, PGS is often used by prospective mothers over age thirty-seven to identify and select embryos with normal chromosomal arrangements for implantation.
The cell biopsies performed during PGD and PGS can traumatize the embryo, so the procedures are usually only reserved for identifying genetic defects and reducing disease risk. In some situations, however, parents may use genetic testing to select embryos with other desired traits, such as a certain gender, eye color, or hair color. One of the first such cases to receive widespread publicity occurred in 1996, when a Virginia couple, Scott and Monique Collins, used PGD to choose a female embryo in an effort to balance their family, which already included two boys.
Genetic Modification of Human Embryos
Advances in the field of genetic engineering have made it possible to modify or alter the genes of living organisms. One of the most promising gene-editing technologies implements clustered regularly interspaced short palindromic repeats (CRISPR), which involve a repeating sequence of genetic code that is extracted from bacteria. Scientists can program CRISPR to target specific DNA sequences in living cells and use an enzyme to make precise cuts in the DNA strands. The CRISPR technique can be used to delete, replace, or insert new genes, causing permanent changes to the organism’s genetic code.
Genetic modification has been performed extensively on plants and animals to impart disease resistance and increase food production, yet ethical concerns and legal prohibitions have historically limited experimentation on humans in clinical trials to gene therapy—applications that use a virus as a vector to deliver healthy DNA to cells in an effort to treat disease. Gene therapy is used to affect somatic cells, which are the differentiated cells that make up major organs like the eyes or lungs, so the changes only affect the individual who undergoes the procedure. When genetic engineering is performed on reproductive cells, such as eggs, sperm, or early-stage embryos, however, the genetic changes and any resulting effects are passed down to future generations. Genetic engineering that produces heritable changes to DNA is known as germline modification.
In July 2017, a team of researchers in Oregon announced that they had successfully used the CRISPR technique to modify the genes of dozens of human embryos. The embryos were created for the experiment through IVF using eggs and sperm donated by people who carried genetic diseases. After the scientists edited the genomes to correct the faulty genes, they destroyed the embryos, thus preventing the changes from modifying the germline and affecting future generations. Although earlier embryonic gene-editing attempts by researchers in China had raised concerns by introducing dangerous mutations into the DNA of the embryos they used, the American team overcame the problem by introducing CRISPR at an earlier point in the reproductive process.
Arguments Against Genetic Modification
The creation of genetically modified human embryos raises many ethical questions. CRISPR technology gives scientists the ability to permanently change the genetic makeup of a human being, as well as that person’s future offspring, without their permission. Germline modification is so new and untested, according to opponents, that its unpredictable results may expose future generations to unforeseen risks that outweigh the potential benefits. Many countries have outlawed or placed a moratorium on germline modification of embryos. In the United States, discomfort with the idea convinced Congress to pass a bill in 2015 that prohibits the Food and Drug Administration (FDA) from approving clinical trials that would produce genetically modified human embryos. That year, the National Institutes of Health (NIH) also affirmed its ban on genetic editing of human embryos, but in 2016, the NIH approved a clinical trial of CRISPR gene-editing technology as a therapy for cancer patients. The following year, the US National Academy of Sciences released an advisory statement supporting limited research into embryonic genetic modification for the purpose of eliminating disease.
Although proponents envision CRISPR being used to correct genetic defects and eradicate inherited diseases, critics foresee the possibility of nontherapeutic uses as well. For instance, they claim that genetic intervention could be used to create designer babies with above-average intelligence, attractiveness, athletic ability, or longevity. They also argue that the expense associated with IVF procedures would make genetic enhancement an option only for wealthy families, potentially creating a two-tiered society in which the poor would face insurmountable genetic disadvantages. Other critics fear that gene-editing technology could be misused by governments to create a superhuman race with improved strength and endurance for military purposes.
Some people object to genetic enhancement on religious or philosophical grounds. They argue that scientists should not “play God” by interfering with biological processes and changing the natural progression of human evolution. They claim that routine correction of genetic differences could reduce the diversity of the human race and leave people vulnerable to new diseases and environmental threats. Some people with disabilities resulting from inherited factors resist the idea of genetic intervention as well. They argue that it promotes the view that they are abnormal or inferior and should be fixed, which can lead to discrimination.
Concerns about the genetic modification of human beings are widespread in the United States. A 2016 STAT-Harvard poll found that 65 percent of Americans felt it should be illegal to genetically engineer embryos to reduce inherited disease risk, while 83 percent believed it should be illegal to genetically enhance embryos to improve such traits as intelligence or attractiveness.
Arguments in Support of Genetic Modification
Genetic modification receives a great deal of support within the scientific community, as well as from adherents of the intellectual movement known as transhumanism. Transhumanists believe that resources should be dedicated to developing new technologies that can eliminate physical and intellectual limitations and increase human potential. They view genetic enhancement as a valuable tool in the pursuit of this goal. Supporters in the scientific community argue that genetic modification of embryos has the potential to cure inherited diseases and disorders and increase the quality of life for generations of people. They promote responsible research aimed at improving human health and welfare.
Advocates of genetic engineering also point out that parents have a natural desire to produce children who are strong, healthy, intelligent, and attractive. Many people exercise their reproductive freedom to choose mates that are likely to imbue their children with these desirable qualities. Proponents claim that genetic enhancement is another tool for people to use to select or improve upon certain traits in their offspring. They argue that creating designer babies should be a personal choice for parents to make without judgment from society or interference from regulatory bodies. Advocates also note that many people take steps to improve themselves as adults. For instance, they apply makeup to appear more attractive, exercise to increase their physical fitness, and pursue education to increase their intelligence. Since society generally approves of these efforts and views self-improvement as a worthwhile goal, proponents argue that genetic enhancement may enjoy greater public acceptance as the technology continues to develop and becomes more commonplace.