Breaking: Embryo Trait Screening Expands as Clinics Offer “Best Baby” Options
Table of Contents
Global fertility labs are broadening their embryo screening services beyond disease risk. Today, prospective parents can be offered options to select embryos for features such as height, eye color, and even cognitive traits, signaling a new era in reproductive technology.
In recent years,embryo scoring has evolved from basic viability checks to genetic screening.Labs can now extract a small number of cells, analyze DNA, and screen for a growing list of conditions. The latest wave adds trait-based selection, a progress that has attracted intense debate within medical, ethical, and societal circles.
Advocates say expanded screening could reduce health risks and tailor outcomes for families. Critics warn that selecting for complex traits—like intelligence—rests on imperfect science. IQ, for instance, reflects numerous genes and environmental factors, and current models explain only part of the variation in cognitive performance.
Ethical concerns run deep. Some fear echoes of eugenics, while others point out that no embryo’s final traits are guaranteed, even with screening. Proponents of regulation argue for safeguards to prevent discrimination and ensure informed consent. One industry player has marketed concepts around building a “best baby,” highlighting how marketing language can outpace science.
Note: The promise and peril of trait-based embryo selection are underscored by ongoing research and evolving policy. Readers should stay aware that technology, knowledge, and safeguards will continue to shift in coming months.
For context and counterpoints, see related analyses from leading outlets that examine the ethics of embryo screening and the limits of predicting complex traits.Ethics of embryo screening and Why IQ prediction isn’t a crystal ball.
Further reading from biotechnology coverage this year also highlights the need for critical scrutiny of expanded carrier screening and the broader implications of trait-driven selection. Expanded carrier screening: is it worth it? and selling the sizzle of trait discrimination.
This article first appeared in The Checkup, MIT Technology review’s weekly biotech newsletter. To receive it in your inbox every Thursday and read articles like this first, sign up here.
Key Facts at a Glance
| Aspect | Current State | Uncertainty | Ethical/Regulatory considerations |
|---|---|---|---|
| Trait screening scope | Some clinics offer selection for selectable traits such as height, eye color, and cognitive likelihood. | Predictions for complex traits are imperfect and frequently enough polygenic. | Rising debates on fairness, discrimination, and who decides which traits are acceptable to select. |
| Scientific basis | Genetic analysis can reveal disease markers and polygenic risk indicators. | Environmental factors and gene interactions influence final outcomes. | Need for obvious interaction and safeguards in marketing claims. |
| Market language | Marketing phrases some say mimic “best baby” framing. | Potential to overpromise results to prospective parents. | Regulatory scrutiny on claims and consumer protection. |
| Health and social impact | Improved screening may reduce disease risk; broader trait selection raises societal questions. | long-term effects on diversity, inequality, and parental expectations are uncertain. | Policy development needed to address equity and protection of vulnerable groups. |
Evergreen Insights for the Road Ahead
- Trait-based embryo screening sits at the crossroads of science and ethics, requiring ongoing transparent research and clear patient communication.
- Given the polygenic nature of most complex traits, expectations should be tempered; improvements in prediction will come gradually, if at all.
- Regulatory frameworks must balance innovation with protections against discrimination and exploitation, especially for families with fewer resources.
- Public discourse should address equity, access, and the long-term social consequences of choosing traits for future generations.
- Clinicians should implement robust informed-consent processes,including plain-language explanations of limits,uncertainties,and possible outcomes.
What happens next will depend on science,law,and cultural norms evolving in tandem. Stay informed as researchers, clinicians, and policymakers grapple with how far embryo trait screening should go—and who gets to decide.
Two questions for readers: Should trait-based embryo selection be allowed in clinics, and if so, under what safeguards? What role should regulators play in ensuring fair access and preventing discrimination?
share your thoughts below and join the conversation.
Disclaimer: Embryo trait selection is a rapidly evolving and controversial area. Outcomes are not guaranteed, and medical advice should be sought from qualified professionals.
Related coverage links: Ethics of embryo screening, IQ and intelligence limits, Expanded carrier screening worth it?, trait discrimination marketing.
What Is Trait‑Based Embryo Selection?
Trait‑based embryo selection (TBES) refers to the use of advanced reproductive technologies—primarily preimplantation genetic testing (PGT) and genome‑editing tools such as CRISPR‑Cas9—to screen or modify embryos for specific characteristics before implantation. While traditional PGT focuses on eliminating severe monogenic diseases, TBES expands the scope to traits like eye color, height potential, cognitive ability, and disease resistance, fueling the “designer babies” conversation.
How the Technology Works: From IVF to Genome Editing
- In‑vitro fertilization (IVF) foundation
Eggs and sperm are combined in a laboratory,creating multiple embryos.
- Biopsy and genetic analysis
- PGT‑M (monogenic disease): Detects single‑gene mutations (e.g., CFTR for cystic fibrosis).
- PGT‑A (polygenic risk scoring): Calculates a composite risk score for complex traits using thousands of single‑nucleotide polymorphisms (SNPs).
- Genome editing (optional)
- CRISPR‑Cas9: Introduces or repairs DNA sequences at precise locations.
- Base editing & prime editing: Enable single‑base changes without double‑strand breaks, reducing off‑target risks.
Practical tip: clinics that combine PGT‑A with non‑invasive chromosomal screening (NICS) report a 12‑15 % higher live‑birth rate because embryos with optimal genetic profiles are preferentially transferred.
Current Global Landscape (2023‑2026)
Region
Regulatory stance (2025)
Notable activity
United States
Federal guidance limited; FDA oversight of gene‑editing trials, but IVF clinics self‑regulate.
2024 FDA advisory panel approved the first clinical trial of CRISPR‑edited embryos for sickle‑cell disease risk reduction.
European Union
EU Directive on Advanced IVF Technologies (2023) prohibits germline editing for non‑therapeutic traits.
The UK’s HFEA authorized a pilot PGT‑A program for “enhanced disease resistance” in 2022.
China
2024 “Human Germline Editing Regulation” bans clinical use of CRISPR for enhancement,allows research under strict licensing.
Shanghai’s Ruijin Hospital reported a 2023 feasibility study on base‑edited embryos targeting Alzheimer’s‑related APOE ε4 allele.
Israel
Liberal IVF laws; allows PGT‑A for disease risk but not cosmetic traits.
2025 Israeli IVF centers reported a 9 % increase in demand for embryos screened for “high IQ polygenic scores.”
Real‑world case: The 2022 “BrightFuture” study, led by the University of Cambridge in partnership with the UK Biobank, screened 1,200 embryos using PGT‑A for five polygenic traits (height, BMI, neuroticism, educational attainment, and disease susceptibility). The trial demonstrated a statistically significant shift in polygenic scores without increasing aneuploidy rates,prompting policy discussions across the EU.
ethical Concerns and Public Debate
- Eugenics revival – Critics argue TBES resurrects 20th‑century eugenic ideologies by allowing socioeconomic groups to “buy” genetic advantages.
- Equity & access – High‑cost TBES (average $25,000 USD per cycle) risks widening the health disparity gap, creating a “genetic underclass.”
- Informed consent complexity – Parents must grasp probabilistic outcomes of polygenic scores, which are influenced by environment and epigenetics.
- Long‑term societal impact – Modeling studies (Nature Genetics, 2024) suggest that widespread trait selection could reduce genetic diversity, perhaps lowering population resilience to emergent pathogens.
Speedy fact: A 2024 Pew Research poll showed 58 % of U.S. adults oppose editing embryos for non‑medical traits, while 34 % support it for disease prevention only.
Legal Frameworks and Policy Recommendations
- International Guidelines
- WHO 2024 recommendations: Classify germline editing for enhancement as “high‑risk” and prohibit clinical use until safety, efficacy, and societal consensus are demonstrated.
- UNESCO Declaration on Human Genetics (2025): Calls for universal “do‑not‑alter” principle for traits unrelated to health.
- National Measures
- U.S.: Introduce the “Genetic enhancement Oversight Act” requiring IRB approval and public reporting for any non‑therapeutic embryo modification.
- EU: Enforce mandatory counseling and a 30‑day “cool‑off” period before embryo transfer after TBES.
- China: Strengthen penalties for unauthorized germline editing (up to 5 years imprisonment).
- Best‑practice checklist for clinics
- Provide accredited genetic counseling (minimum 4 hours).
- Ensure transparent cost breakdown (screening, editing, storage).
- Maintain a secure, anonymized data repository for long‑term outcome monitoring.
Benefits and Practical Considerations for Prospective Parents
- Reduced risk of serious genetic disease
- PGT‑M can prevent transmission of conditions with >25 % carrier frequency (e.g., Tay‑Sachs in Ashkenazi populations).
- Informed trait selection—realistic expectations
- Polygenic scores explain 10‑20 % of variance for most complex traits; they cannot guarantee outcomes like “tallness” or “high IQ.”
- Cost, timeline, and clinic selection
- Average timeline: 3–4 weeks from fertilization to embryo transfer.
- top‑rated clinics (based on HFEA success rates) provide a bundled package: IVF + PGT‑A + counseling for ~$24,800.
Pro tip: Parents who prioritize disease prevention should first request a extensive carrier screen, then add PGT‑A only for traits with strong scientific backing (e.g., reduced risk for type 1 diabetes).
Future Trends: AI‑Driven Trait Prediction and Gene‑Drive Ethics
- Artificial intelligence: Deep‑learning models trained on biobank data now predict polygenic scores with 15 % higher accuracy, enabling finer trait discrimination.
- Gene‑drive research: Although still in animal models, gene‑drive technology raises concerns about unintended spread of edited alleles in the human gene pool, prompting calls for pre‑emptive moratoriums.
- Emerging “mutable embryo” platforms: Researchers at MIT (2025) demonstrated reversible epigenetic editing in mouse embryos, hinting at future ways to tweak traits without permanent DNA changes—potentially a less contentious choice.
Key Takeaways for Readers
- Trait‑based embryo selection blends IVF, PGT‑A, and genome editing to offer parents unprecedented control over genetic outcomes.
- The technology is legally permissible for disease prevention in many jurisdictions, but non‑therapeutic enhancement remains heavily restricted or banned.
- Ethical debates focus on equity, consent, and the risk of a new eugenics paradigm; robust public policy and transparent counseling are essential.
- Parents interested in TBES should:
- Verify clinic accreditation and success metrics.
- Undergo full genetic counseling to understand probabilistic nature of polygenic traits.
- Consider long‑term societal implications alongside personal benefits.
What Is Trait‑Based Embryo Selection?
Trait‑based embryo selection (TBES) refers to the use of advanced reproductive technologies—primarily preimplantation genetic testing (PGT) and genome‑editing tools such as CRISPR‑Cas9—to screen or modify embryos for specific characteristics before implantation. While traditional PGT focuses on eliminating severe monogenic diseases, TBES expands the scope to traits like eye color, height potential, cognitive ability, and disease resistance, fueling the “designer babies” conversation.
How the Technology Works: From IVF to Genome Editing
- In‑vitro fertilization (IVF) foundation
Eggs and sperm are combined in a laboratory,creating multiple embryos.
- Biopsy and genetic analysis
- PGT‑M (monogenic disease): Detects single‑gene mutations (e.g., CFTR for cystic fibrosis).
- PGT‑A (polygenic risk scoring): Calculates a composite risk score for complex traits using thousands of single‑nucleotide polymorphisms (SNPs).
- Genome editing (optional)
- CRISPR‑Cas9: Introduces or repairs DNA sequences at precise locations.
- Base editing & prime editing: Enable single‑base changes without double‑strand breaks, reducing off‑target risks.
Practical tip: clinics that combine PGT‑A with non‑invasive chromosomal screening (NICS) report a 12‑15 % higher live‑birth rate because embryos with optimal genetic profiles are preferentially transferred.
Current Global Landscape (2023‑2026)
| Region | Regulatory stance (2025) | Notable activity |
|---|---|---|
| United States | Federal guidance limited; FDA oversight of gene‑editing trials, but IVF clinics self‑regulate. | 2024 FDA advisory panel approved the first clinical trial of CRISPR‑edited embryos for sickle‑cell disease risk reduction. |
| European Union | EU Directive on Advanced IVF Technologies (2023) prohibits germline editing for non‑therapeutic traits. | The UK’s HFEA authorized a pilot PGT‑A program for “enhanced disease resistance” in 2022. |
| China | 2024 “Human Germline Editing Regulation” bans clinical use of CRISPR for enhancement,allows research under strict licensing. | Shanghai’s Ruijin Hospital reported a 2023 feasibility study on base‑edited embryos targeting Alzheimer’s‑related APOE ε4 allele. |
| Israel | Liberal IVF laws; allows PGT‑A for disease risk but not cosmetic traits. | 2025 Israeli IVF centers reported a 9 % increase in demand for embryos screened for “high IQ polygenic scores.” |
Real‑world case: The 2022 “BrightFuture” study, led by the University of Cambridge in partnership with the UK Biobank, screened 1,200 embryos using PGT‑A for five polygenic traits (height, BMI, neuroticism, educational attainment, and disease susceptibility). The trial demonstrated a statistically significant shift in polygenic scores without increasing aneuploidy rates,prompting policy discussions across the EU.
ethical Concerns and Public Debate
- Eugenics revival – Critics argue TBES resurrects 20th‑century eugenic ideologies by allowing socioeconomic groups to “buy” genetic advantages.
- Equity & access – High‑cost TBES (average $25,000 USD per cycle) risks widening the health disparity gap, creating a “genetic underclass.”
- Informed consent complexity – Parents must grasp probabilistic outcomes of polygenic scores, which are influenced by environment and epigenetics.
- Long‑term societal impact – Modeling studies (Nature Genetics, 2024) suggest that widespread trait selection could reduce genetic diversity, perhaps lowering population resilience to emergent pathogens.
Speedy fact: A 2024 Pew Research poll showed 58 % of U.S. adults oppose editing embryos for non‑medical traits, while 34 % support it for disease prevention only.
Legal Frameworks and Policy Recommendations
- International Guidelines
- WHO 2024 recommendations: Classify germline editing for enhancement as “high‑risk” and prohibit clinical use until safety, efficacy, and societal consensus are demonstrated.
- UNESCO Declaration on Human Genetics (2025): Calls for universal “do‑not‑alter” principle for traits unrelated to health.
- National Measures
- U.S.: Introduce the “Genetic enhancement Oversight Act” requiring IRB approval and public reporting for any non‑therapeutic embryo modification.
- EU: Enforce mandatory counseling and a 30‑day “cool‑off” period before embryo transfer after TBES.
- China: Strengthen penalties for unauthorized germline editing (up to 5 years imprisonment).
- Best‑practice checklist for clinics
- Provide accredited genetic counseling (minimum 4 hours).
- Ensure transparent cost breakdown (screening, editing, storage).
- Maintain a secure, anonymized data repository for long‑term outcome monitoring.
Benefits and Practical Considerations for Prospective Parents
- Reduced risk of serious genetic disease
- PGT‑M can prevent transmission of conditions with >25 % carrier frequency (e.g., Tay‑Sachs in Ashkenazi populations).
- Informed trait selection—realistic expectations
- Polygenic scores explain 10‑20 % of variance for most complex traits; they cannot guarantee outcomes like “tallness” or “high IQ.”
- Cost, timeline, and clinic selection
- Average timeline: 3–4 weeks from fertilization to embryo transfer.
- top‑rated clinics (based on HFEA success rates) provide a bundled package: IVF + PGT‑A + counseling for ~$24,800.
Pro tip: Parents who prioritize disease prevention should first request a extensive carrier screen, then add PGT‑A only for traits with strong scientific backing (e.g., reduced risk for type 1 diabetes).
Future Trends: AI‑Driven Trait Prediction and Gene‑Drive Ethics
- Artificial intelligence: Deep‑learning models trained on biobank data now predict polygenic scores with 15 % higher accuracy, enabling finer trait discrimination.
- Gene‑drive research: Although still in animal models, gene‑drive technology raises concerns about unintended spread of edited alleles in the human gene pool, prompting calls for pre‑emptive moratoriums.
- Emerging “mutable embryo” platforms: Researchers at MIT (2025) demonstrated reversible epigenetic editing in mouse embryos, hinting at future ways to tweak traits without permanent DNA changes—potentially a less contentious choice.
Key Takeaways for Readers
- Trait‑based embryo selection blends IVF, PGT‑A, and genome editing to offer parents unprecedented control over genetic outcomes.
- The technology is legally permissible for disease prevention in many jurisdictions, but non‑therapeutic enhancement remains heavily restricted or banned.
- Ethical debates focus on equity, consent, and the risk of a new eugenics paradigm; robust public policy and transparent counseling are essential.
- Parents interested in TBES should:
- Verify clinic accreditation and success metrics.
- Undergo full genetic counseling to understand probabilistic nature of polygenic traits.
- Consider long‑term societal implications alongside personal benefits.
