As British scientists lobby for permission to create three-parent embryos, some bioethicists are calling for the creation of four-parent babies. In an article for the November edition of the Journal of Medical Ethics, John Harris, César Palacios-González, and Giuseppe Testa suggest using stem cells to create eggs and sperm (in vitro generated gametes or IVG) to allow for “multiplex parenting.”

The bioethicists note that the ability to create stem cells out of adult somatic cells instead of relying on embryonic stem cells makes their plan much more workable. Scientists have been able to create eggs and sperm from the somatic cells of mice. They also grew the precursors of human sperm cells.

The bioethicists brush aside concerns about the health of children created using this method by noting that the effects would be studied extensively in animal models before they are applied to humans. They also note that the procedure of IVF was put under much less scrutiny when it was applied to human reproduction. Moreover, “allowing relatively older men to reproduce ‘naturally’ is already now causing effects that in the cause of EVG could be brought up only hypothetically” such as mental disabilities.

They also argue that the procedure of IVG is good for the children because without it, they would never have existed at all. For instance, “if the woman chooses not to use IVG and instead conceives by natural procreative means, or other assisted reproduction technologies, the child born will be a completely different one.”

IVG would make it possible for infertile couples to have children. Going further, they suggest that society considers allowing individuals to self-reproduce using sperm and egg cells made from their own DNA. They also envisage that IVG would make it possible for both people in a same-sex relationship to become genetic parents.

The authors of the paper use the recent controversy over three-parent embryos to bolster their claim. In 2013, the UK’s Human Fertilisation and Embryology Authority recommended that mitochondrial DNA from a third person be used to prevent serious genetic diseases from developing in the existing embryo.

IVG would go further: “First, two embryos would be generated from either couple through IVF with either naturally or in vitro generated gametes. hESC (human embryonic stem cell) lines would then be 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 grandparents.” They brush aside the importance of the “nuclear” family, noting that it is “just one, and for that matter relatively recent configuration in the history of human relationships.”

The authors are not concerned about the psychological impact of such a family model would have on the children of such relationships, as “the children born through this application of IVG would not be harmed by being brought into existence because the only other option would be never to have been at all.”