🇩🇪 Deutsche Version: In-vitro-Gametogenese (IVG)

Note: The ethical judgments on this page refer exclusively to the action — never to the person who performs it or who came into existence through it. Cf. Note on ethical judgments (German).

In vitro gametogenesis is the production of germ cells from cells that do not derive from the germline — as a rule from induced pluripotent stem cells, themselves obtained from body cells.

In mice it has fully succeeded: in 2016 living offspring were produced from stem-cell-derived oocytes. In humans the path to a mature oocyte has so far not been completed.

Ontological classification

is subclass of: genetic technology
presupposes: reprogramming of a body cell
has subclass: in vitro oogenesis and in vitro spermatogenesis
is not a subclass of artificial fertilization: IVG produces gametes, not a fertilization — it is prior to it

The difference from nuclear transfer

Both routes aim at the same thing: an oocyte for a woman who has none. They differ fundamentally in how they accomplish the halving of the chromosome set.

On the stem cell route the cells are returned to the germline and there pass through meiosis from prophase I to metaphase II, because the entire developmental programme is rebuilt rather than skipped. With a qualification: the 2016 mouse study documents the progression of meiotic stages but not a recombination assay of its own, and it reports an elevated rate of incomplete chromosome pairing as well as more frequent deviant chromosome counts. Nuclear transfer skips it and must subsequently force the halving; precisely there mitomeiosis fails.

The price of the stem cell route is a different one: it requires rebuilding the entire female germline in the laboratory — primordial germ cells, oogonia, follicle-like structures, then months of growth. Every stage of this cascade can yield cells with a subtly wrong epigenome. One advantage remains: it needs no donor oocyte.

The landscape of arguments

Critical positions. The sharpest objection from scale is in vitro eugenics: not selection within a cohort of embryos, but iterated selection across laboratory generations — stem cells from selected embryos, gametes from those, the next generation from those. Selective breeding without the time constraint of human generations. Alongside stands the forecast that cheap genome sequencing will enable selection from around a hundred fully sequenced embryos per couple; it is advanced expressly without normative commitment and is prediction, not condemnation. Further objections concern solo reproduction, the production of offspring from another’s cell material without consent, safety for the child, and heritable consequences.

Supporting positions. IVG is defended chiefly via reproductive autonomy and equal treatment of same-sex couples; a further argument sees in it the end of gamete donation together with the burdens this imposes on donors. For the nuclear-transfer route, however, this last argument precisely does not hold: it consumes donor oocytes rather than replacing them.

Institutional. The German Ethics Council has called for more precise legal definitions of “embryo” and “totipotency” with respect to artificially produced germ cells. The Nuffield Council presented a detailed review in 2025; the American professional body ASRM published the first dedicated ethics opinion in 2026. The ISSCR currently classifies IVG for reproductive purposes as impermissible — but on safety grounds, hence as a moratorium, not as a prohibition in principle. Ontologically that is a different type of norm from the prohibition of cloning.

The regulatory gap

Nowhere in the world does a law explicitly name and regulate the production of germ cells from body cells. Governance operates everywhere indirectly.

The British case is the most differentiated, and it displays the pattern: a permitted egg is there defined in law as one produced by or extracted from the ovaries of a woman. Because IVG oocytes are neither produced there nor extracted from there, they are not permitted eggs — and their reproductive use is thereby excluded. That is a reflex effect, not a prohibition of production. Japan has guidelines permitting production and forbidding fertilization, but these are administrative guidelines, not an act of parliament. In Germany IVG is not envisaged in the statute; whether an oocyte so obtained counts as an “egg” within the relevant criminal provision is contested and judicially unresolved.

Ethical assessment

For in vitro gametogenesis there exists no magisterial document. This is a robust finding, not a gap in research — and it does not mean that an assessment is outstanding. The personhood ontology grounds its judgments in ontological dignity and the Personalist Norm following from it, not in documents. It can therefore judge even where no one has yet spoken. The three points below are applications of that norm to the procedure.

First: selection by characteristics as the normal case

The core of oblivion of the person is, on this ontology, to affirm a person not for her own sake but on account of her characteristics. That is exactly the structure of every embryo selection — and in vitro gametogenesis changes nothing qualitative about it, but a great deal about its scale.

That is the decisive point. So long as few embryos issue from a treatment, selection remains an exception. Where a procedure permits a hundred embryos per couple, it becomes the normal case, and the criterion of selection migrates from warding off severe disease to optimization by preference. Oblivion of the person thereby ceases to be a marginal case and becomes the form of the procedure. Sparrow’s in vitro eugenics extends the same structure across generations.

Second: production and consumption in the First Dimension

Every embryo produced is a person in the First Dimension — spiritual substance in a body with active potency toward the unfolding of consciousness, with a full right to life. The planned production of embryos in numbers that presuppose the consumption of the majority makes that consumption a means to an alien end. By the fontes moralitatis the object of the action determines its moral species; the object here is the production of persons most of whom are meant to be discarded.

Third: disposing over the one brought forth

With uniparental reproduction an independent violation is added. Whoever produces a child from two halves of the same genome accepts on that child’s behalf a risk of homozygous damage that follows solely from the chosen mode of generation and that the one affected could never choose. That is instrumentalization in the precise sense: the one brought forth bears the consequences of a decision that makes him a means to another’s wish.

What the ontology does not condemn here

The production of a germ cell from a body cell is in itself no action upon a person. A gamete is no candidate for personhood, and the norm does not reach into a void. Condemnation begins only where persons are affected: with the embryo produced, with the child brought forth. Whoever wishes to reject the procedure as such would have to show that merely producing a germ cell disregards a person — and that argument the ontology does not supply.

Corroboration, as confirmation and not as ground: Donum vitae I,6 rejects the production of a human being without connection to sexuality. That is a point of connection and not a statement about this procedure — the distinction matters, because otherwise the impression would arise of a magisterial pronouncement that does not exist.

The strongest objection to this assessment

The argument from scale is vulnerable. The Nuffield report notes that a strictly indication-bound regulation of embryo selection mitigates the feared expansion; the concern is acute above all where regulation is less stringent. But then the argument is not directed against in vitro gametogenesis at all, but against lax rules of selection — and would strike preimplantation genetic testing in its present form just as hard.

The personal-ontological answer cuts both ways. It must concede that oblivion of the person lies not in the technique but in the logic of selection the technique makes available. And it must admit that the ontology thereby argues against existing practice and not merely against a future one. Whoever shares the critique of in vitro gametogenesis while accepting preimplantation genetic testing argues inconsistently.

Was den Menschen zum Menschen macht

Übersicht

In Vitro Gametogenesis (IVG)