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Preimplantation Genetic Diagnosis

6 Min. Lesezeit

🇩🇪 PGT)

Note: The ethical judgments on this page refer exclusively to the action — never to the person who performs it. Every person possesses inalienable dignity, regardless of what they do or have done. Cf. Note on ethical judgments (German).

Preimplantation genetic diagnosis (PGD; today commonly Preimplantation Genetic Testing, PGT) is the genetic examination of an embryo produced by in vitro fertilization prior to transfer into the uterus. Its declared aim is to exclude embryos with particular genetic characteristics from transfer.

PGD necessarily presupposes IVF and creates a selection situation: several embryos are produced, tested, and — depending on the findings — transferred, cryopreserved, or discarded. Since every embryo is a human person with full ontological dignity — from fertilization onward, in the First Dimension (prote energeia) — the selective sorting-out is a form of practical oblivion of the person and stands in tension with the Personalist Norm.

Ontological classification

Ontological relations:

Types of procedure

Four types of procedure can be distinguished, with differing ethical weight:

PGT-M — Monogenic conditions

Detection of monogenic hereditary diseases (e.g. Huntington’s disease, cystic fibrosis, muscular dystrophy). In Germany, Austria, and Switzerland permitted only in exceptional cases and after an ethics committee ruling; in the United Kingdom indication-bound through the HFEA. Even where the indication is medically grounded, the logic of selection remains ethically problematic: an embryo with a positive finding is not healed but discarded.

PGT-SR — Structural chromosomal rearrangements

Detection of structural chromosomal changes (translocations, inversions) in couples with a known risk of recurrent miscarriage. The medical motive — to avoid recurrent miscarriage — is understandable, yet it does not change the logic of selection: embryos with structural rearrangements are not healed but excluded from transfer.

PGT-A — Aneuploidy screening

Detection of aneuploidies (e.g. trisomy 21). Unlike PGT-M/PGT-SR, it is applied without a familial indication, as a general IVF quality filter. Its clinical benefit is disputed and it is especially problematic ethically, since embryos with trisomies — for instance with Down syndrome — are deliberately sorted out. The sorting-out occurs not from a perspective of healing but on account of a genetic particularity.

PGT-P — Polygenic traits

Estimation of polygenic risk scores (e.g. heart disease, diabetes, schizophrenia, IQ proxy, height). The Ethics Committee of the American Society for Reproductive Medicine (ASRM) determined in 2025 that PGT-P is not clinically ready and may not be used for the non-medical selection of traits. Ontologically, PGT-P shifts the logic of selection from the warding-off of disease to the optimization of the desired child, and is thus clearly eugenic in the broader sense.

Special forms

Savior-sibling selection

Use of PGT to select an embryo whose HLA profile matches a sick sibling, so that umbilical-cord blood or stem cells can later be donated. The new human being is deliberately produced as a means to another’s end — a classic violation of the Personalist Norm: the person may never be a mere means.

Non-medical sex selection

Selection of embryos by sex for non-medical reasons (family balancing). Rejected in the EU — Oviedo Convention, Art. 14 — and by the ASRM ethics opinion; in several countries (India, China) the practice has led to demographic imbalances between the sexes. Ontologically a selection by desired characteristic.

The global regulatory spectrum ranges from near-total prohibition to largely unrestricted application:

  • Italy: near-total prohibition.
  • Germany, Austria, Switzerland: prohibited in principle, exceptionally permitted in cases of severe hereditary disease and after the ruling of an ethics committee.
  • United Kingdom: PGT-M, PGT-SR, and PGT-A permitted on an indication-bound basis through the HFEA.
  • Japan: PGT-M only for severe monogenic conditions, with case-by-case review by the JSOG.
  • Belgium, the Netherlands, Scandinavia: permitted on an indication-bound basis; eugenic trait selection rejected.
  • USA: no federal regulation; application at the discretion of reproductive physicians and their patients.
  • India, China: largely unregulated under their own law; sex selection has led to demographic distortions.

ELSI research (Ethical, Legal, Social Implications) has recorded a tenfold increase in publications on PGT since 1999; 86 % of the literature, however, originates from only twelve countries — the global ethical framing remains heterogeneous.

Ethical classification

The ontology of personhood takes a clear position:

  • PGT-M and PGT-SR stand in the field of tension between the medical motive and the logic of selection. The good intention diminishes the subjective culpability but does not change the object of the action (fontes moralitatis): the diagnosed embryo is not healed but discarded.
  • PGT-A, PGT-P, savior-sibling selection, and non-medical sex selection are morally illegitimate. They violate the Personalist Norm by affirming or sorting out the person according to characteristics, instead of accepting them for their own sake.

The assessment rests on two insights: (1) every embryo is a person with full dignity from fertilization onward; (2) the core of the oblivion of the person consists in affirming the person not for their own sake but on account of their characteristics.

See also

Sources: Generated by querying the Personhood ontology. Bexten 2017, pp. 293–306 (practical oblivion of the person), pp. 202–204 (personhood from the very beginning).

Further sources:

  • German Ethics Council (Deutscher Ethikrat) (2011): Präimplantationsdiagnostik — Stellungnahme (opinion).
  • Convention on Human Rights and Biomedicine (Oviedo Convention, Council of Europe, 1997), Art. 14.
  • ASRM Ethics Committee (2025): Use of preimplantation genetic testing for polygenic disorders (PGT-P): an Ethics Committee opinion. Fertility and Sterility.
  • ASRM Ethics and Practice Committees (2025): joint report concluding that polygenic embryo screening is not ready for clinical use.
  • Sueoka, K. (2025): Balancing ethics and clinical need: The Japanese experience with preimplantation genetic testing for monogenic disease regulation and implementation. Journal of Obstetrics and Gynaecology Research 51(8).
  • Alon, I., Bussod, I. & Ravitsky, V. (2024): Mapping ethical, legal, and social implications (ELSI) of preimplantation genetic testing (PGT). Journal of Assisted Reproduction and Genetics.
  • Congregation for the Doctrine of the Faith (2008): Dignitas personae. Instruction on Certain Bioethical Questions.

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