Polygenic Embryo Selection and the Future of IVF: Science Nearing Prime Time

When my son was conceived through IVF twenty-one years ago, embryo selection was almost entirely visual. Clinicians looked for the “best-looking” embryo—symmetrical, healthy-appearing, vibrant under the microscope.

It was, in hindsight, a rudimentary form of genetic selection. We weren’t sequencing DNA, but we were making judgments based on perceived viability.

Even then, I felt the tension between scientific wonder and social unease—questions of control, randomness, and what it means to intervene in creation.

From Single-Gene Testing to Polygenic Risk Scores (PRS) and Polygenic Scoringing

Traditional preimplantation genetic testing (PGT) screens for clear-cut conditions: chromosomal abnormalities or mutations in a single gene, such as cystic fibrosis or Tay-Sachs. Polygenic embryo screening (PES) introduces a different layer of complexity. Instead of identifying one defective gene, PES uses polygenic risk scores (PRS), a composite of thousands of small genetic variations, to estimate the probability that an embryo might later develop a polygenic disease like heart disease, diabetes, or schizophrenia.

Parents undergoing IVF could, in theory, compare embryos based on these probabilistic scores, choosing one with a lower estimated risk for chronic disease or higher likelihood of longevity. What was once morphological intuition is now becoming data-driven prediction.

How Polygenic Embryo Screening Works

1. Genetic Sampling – Embryos created via IVF undergo biopsy to extract DNA.

2. PRS Calculation – Algorithms aggregate the effects of many small genetic variants linked to disease risk.

3. Ranking – Each embryo receives a numerical “score” estimating risk for certain traits or diseases.

4. Selection – Prospective parents may choose to implant embryos with the lowest predicted risk.

Limitations and Concerns

Limited Accuracy and Utility. PRS are population-based estimates, not personal forecasts. Their predictive power is far weaker at the individual or embryonic level. A “low-risk” embryo is not guaranteed a healthy life, and a “high-risk” one may never develop disease.

Ethical Complexity. This technology doesn’t edit or add genes—it reveals existing genetic variation and invites choice. Yet the line between choice and eugenics can blur quickly. Even without manipulation, the act of selecting embryos based on predicted traits raises deep questions about equity, ableism, and social values.

Scientific Uncertainty. Environment, upbringing, and random biological events all influence disease expression. Genes are probability, not prophecy.

Lack of Consensus. Organizations such as the American College of Medical Genetics and Genomics and Harvard Medical School caution that polygenic embryo screening is not ready for clinical use due to accuracy gaps, unvalidated algorithms, and lack of regulatory oversight.

Is This a Slippery Slope Toward Eugenics?

It’s a fair—and urgent—question. The original eugenics movements were driven by governments, institutions, and ideologies seeking to control human breeding. Polygenic embryo selection, at least for now, is driven by individual choice—parents making decisions in private consultation rooms, guided by doctors and data. But that distinction is fragile.

The leap from informed choice to influenced choice can happen quietly. When data-driven health insurers, governments, or fertility companies begin to shape the “recommended” embryo, the ethical calculus shifts.

Who defines “healthy”? Who defines “normal”? And who ensures that freedom of choice remains free from coercion—economic, social, or political?

This is not a far-off thought experiment. The infrastructure for selection already exists. As predictive algorithms advance, the question may no longer be whether we can select against risk, but whether we will be pressured to do so.

The Cultural Reckoning Ahead

The romantic notion of childbirth—its unpredictability, its randomness—is colliding with the precision of genomic prediction. As the tools sharpen, so will the moral debate. I can’t help but think back to my own IVF experience, to the fragile hope in the embryology lab, and to the story I later wrote—“No Cancer”—a piece of flash fiction exploring the emotional gravity of genetic selection that appears in the second edition of The Paper Boy & The Winter War.

Science marches forward, but the questions remain the same: Where do we draw the line between prevention and perfection?

And now, a new horizon looms. There is more—much more—to unfold. Under the gathering shadow of advancing AGI, we are witnessing two accelerating forces: artificial intelligence and genetic selection. Both seek the absence of error—disease, disorder, deviation. Both move at light speed toward a singular conclusion yet to be determined. Whether that endpoint represents human evolution, human editing, or human extinction remains to be seen.

Author: R.E. Hengsterman, MSN, MA, M.E., RN

Registered nurse, night-shift administrator, and author of The Shift Worker’s Paradox

Nursewhowrites.com

For educational purposes only. Not medical advice.