Stop fretting about 3-parent embryos and get ready for
Bioedge, 8 March, 2014
Reproduced under licence
The controversy over three-parent embryos could soon be old hat. Writing
in one of the world's leading journals, one of Britain's best-known
bioethicists has outlined a strategy for creating children with four or more
genetic parents. He calls it "multiplex parenting".
John Harris, of the University of Manchester, and two colleagues, César
Palacios-González and Giuseppe Testa contend in the
Journal of Medical Ethics (free online) that this is one of many
exciting consequences of using stem cells to create synthetic eggs and
sperm. (Or as they prefer to call them, in vitro generated gametes (IVG).)
After the discovery of induced pluripotent stem cells in 2007,
theoretically any cell in the body can be created from something as simple
as a skin cell. Mice have already been born from sperm and eggs created from
stem cells. Harris and his colleagues believe that the day is not far off
when scientists will be able to do the same with humans. In their paper,
they spin an ethical justification for this and outline some possible uses.
First, is it ethical? Of course it is, so long as experiments on mice
show that it is safe. After all, they write, this is already a much higher
ethical bar than the one used for the first IVF babies. "If impractically
high precautionary thresholds were decisive we would not have vaccines, nor
IVF, nor any other advance. Nothing is entirely safe." Besides, any children
brought into the world are better off than if they never existed.
Second, there are many potential uses. The first four are familiar from
the world of IVF: men who cannot produce viable sperm; women with premature
menopause; people who have lost gonads or their fertility due to cancer
treatment; and people who have been involuntarily sterilised (rare, but they
Many clients for such a service would be gay and lesbian couples who
could have children who are genetically related to them both. "There is
nothing morally wrong with same-sex competent caring people using IVG for
satisfying their legitimate interests in becoming genetic parents of their
children," they say.
Another would be "single individuals, who may wish to reproduce without
partner and without resorting to gamete donation". This would be the most
intense form of incest – an individual effectively mating with himself – so
its safety is not guaranteed. But if it were safe, it might be permissible.
Finally, "multiplex parenting", an option which Harris and his colleagues
tackle with great enthusiasm. This is "a radical expansion of reproductive
autonomy that allowed more than two persons to engage simultaneously in
"IVG could permit instead a much more substantive sharing of genetic
kinship, through what is in essence a generational shortcut. Imagine that
four people in a relationship want to parent a child while being all
genetically related to her. IVG would enable the following scenario: first,
two embryos would be generated from either couple through IVF with either
naturally or in vitro generated gametes. hESC lines would be then
established from both embryos and differentiated into IVG to be used in a
second round of IVF. The resulting embryo would be genetically related to
all four prospective parents, who would technically be the child's genetic
But it could be far more than four parents. An
Australian bioethicist has discussed how children with even more
progenitors could be created as a form of in vitro eugenics. By creating
gametes from embryonic stem cells, it would be possible to create 20 or 30
generations of Petri dish humans in as little as ten years. So four parents
might be a conservative estimate. "The in vitro compression of generational
time appears thus like the most transforming feature of IVG derivation,"
An ethical defence of this scenario is tall order. But Harris et al
up to it. In the first place, arguments drawn from what is "natural" are
obviously irrelevant as there is no such thing as "natural" ways of acting.
Hence, what can be wrong with opening up genetic kinship to a wider range of
people than one father and one mother?
If there are some drawbacks, the child can hardly complain. It exists,
and existence is better than non-existence. In any case, even today,
parenting involves many different individuals from different generations.
The use of IVGs merely gives this reality a genetic component. "Prospective
parents will be able to choose among a hitherto unimaginable variety of
potential children," they write.
article was published by Michael Cook and BioEdge.org under a
Creative Commons licence. You may republish it or translate it free of
charge with attribution for non-commercial purposes following
these guidelines. If you teach at a university we ask that your
department make a donation to BioEdge.org. Commercial media must
contact BioEdge.org for permission