The promise of a “best baby” – taller, smarter, healthier – is increasingly being marketed to prospective parents undergoing in vitro fertilization (IVF). A new wave of genetic tests claims to predict these complex traits in embryos, allowing parents to select for desired characteristics. However, experts caution that these tests are largely unproven, offering minimal benefit while potentially introducing significant risks to individuals and society.
While preimplantation genetic testing (PGT) has long been available to screen for single-gene disorders like cystic fibrosis, these newer tests attempt to assess polygenic traits – characteristics influenced by thousands of genes working in concert. Companies like Nucleus Genomics, with marketing campaigns featuring slogans like “Have your best baby,” offer screening for up to 2,000 traits, including eye color, IQ, and predisposition to conditions like Alzheimer’s and heart disease. These tests generate “polygenic risk scores” for each embryo, theoretically indicating their likelihood of developing certain conditions or exhibiting specific traits.
Prospective parents are being marketed genetic tests that claim to predict which IVF embryo will grow into the tallest, smartest or healthiest child.
The Science Behind the Scores
The core of these tests lies in polygenic risk scores, which attempt to quantify an embryo’s genetic predisposition to certain traits. However, research indicates these predictions are far from certain. A recent evaluation of the technology, using the same framework applied to medical screening tests, revealed the predictions to be “extremely uncertain,” according to researchers. The complexity of these traits, influenced by a multitude of genes and environmental factors, makes accurate prediction exceedingly difficult.
Currently, these tests are more readily available in the United States than in countries like Australia. Nucleus Genomics, for example, has extensively advertised its services in New York. The appeal is understandable; the desire to provide a child the best possible start in life is a powerful motivator for many parents. However, the question of what constitutes “best” is inherently subjective and raises ethical concerns.
What Does PGT Actually Do?
Preimplantation genetic testing (PGT) broadly examines embryos created through IVF for genetic problems before they are transferred to the uterus. According to the Women & Infants Fertility Center, PGT can identify embryos with missing or extra chromosomes (like in Down syndrome), single-gene disorders (such as sickle cell anemia), or gene rearrangements that could lead to miscarriage or birth defects. Learn more about PGT here. Preimplantation genetic screening (PGS), also known as preimplantation genetic testing for aneuploidies (PGT-A), specifically identifies the number of chromosomes present in each embryo, aiming to prevent implantation failure, pregnancy loss, and health problems in the baby. PFCLA details the pros and cons of PGS/PGT-A.
Risks and Ethical Considerations
The potential risks associated with these predictive tests extend beyond their scientific limitations. Experts worry about the societal implications of selecting embryos based on desired traits, potentially exacerbating existing inequalities and leading to a form of genetic enhancement. The focus on traits like height and IQ raises concerns about valuing certain characteristics over others and devaluing individuals who do not possess them. The accuracy of these tests is questionable, and relying on them could lead to the discarding of healthy embryos.
The UCSF Center for Reproductive Health distinguishes between different types of genetic testing, including preimplantation genetic testing for aneuploidy (PGT-A) and other forms of PGT. Find more information on genetic testing at UCSF. It’s important to remember that PGT serves as a “quality-control step” in IVF, screening embryos for existing genetic defects, rather than predicting future traits with certainty, as highlighted by the Fertility Institute of Hawaii. Read more about genetic testing before IVF.
Looking Ahead
As these technologies continue to develop, it is crucial that prospective parents receive accurate and unbiased information about their limitations and potential risks. The marketing of these tests should be carefully scrutinized, and regulatory oversight may be necessary to ensure responsible use. The ethical and societal implications of selecting embryos based on predicted traits require ongoing discussion and debate. The future of reproductive technology hinges on a commitment to scientific rigor, ethical considerations, and the well-being of both individuals and society.
What are your thoughts on the ethical implications of embryo selection? Share your perspective in the comments below.
Disclaimer: This article provides informational content only and is not intended to be a substitute for professional medical advice. Always consult with a qualified healthcare provider for any questions you may have regarding your health or treatment.
