In Vitro Gametogenesis and the Evolution of Parenting
Exploring new frontiers in reproduction and family structure
In vitro gametogenesis (IVG) is the production of gametes (i.e., sperm and eggs) outside the body. IVG has been achieved in mice (Hikabe et al., 2016), and some anticipate that IVG will be achieved in humans relatively soon. IVG is an extremely important discovery because it could potentially improve the accessibility and efficacy of in vitro fertilization (IVF), enable same-sex couples to have biological offspring, and increase the returns from polygenic embryo screening.
Another interesting, although less impactful, implication of IVG is the possibility of multiplex parenting (Palacios-González et al., 2014). Since IVG enables the derivation of sperm and eggs from stem cells, it would facilitate the ability to skip generations; two couples could produce embryos, and one couple could use the embryonic stem cells of their embryos to create eggs while the other uses stem cells from their embryo to create sperm. The sperm and egg can then be combined to produce more embryos. The two couples would be genetically related to each resulting embryo, making them genetically equivalent to grandparents, with the parent generation existing entirely in vitro.
IVG would enable many different unusual parenting arrangements. For example, you could have one couple who contributes an egg cell derived from an embryo that they create and one individual who contributes his sperm. In this arrangement, you would have three contributors, but two are as genetically related as grandparents, while one is as genetically related as a parent. You could also add many more generations. For example, groups of 8, 16, 32, 64, 128, and so forth people could each make an equal contribution to a resulting set of embryos.
Couples may opt for such an arrangement for a variety of reasons. One important and perhaps highly motivating reason would be that the resulting offspring could be extraordinarily healthier, happier, and more intelligent if polygenic embryo screening were applied at each stage. This process is known as Iterated Embryo Selection and would have extremely large benefits (see Branwen, 2016). With a highly polygenic trait like intelligence, there are enough genetic variants that a deliberate process of repeated embryo screening could produce people more intelligent than anyone who has ever existed (Hsu, 2014).
Many skeptics express concerns about the impact of reprogenetic technology on inequality and its association with the eugenics movement. A less-explored aspect of this technology is the implications on family structure. One 2016 article, “In vitro gametogenesis: just another way to have a baby?” by Sonia M. Suter, discusses some possible concerns that bioethicists might raise. For example, children might feel bad that they never got to meet their actual parents because they only existed in vitro. Another concern might be that children feel unattached from any parent because there is so little genetic contribution from any given parent. Perhaps most concerning would be how legal custody and parental rights would be determined, especially in the case of divorce.
Despite the ethical concerns, it is worth considering some positives to being a child or parent in a multiplex parenting arrangement:
The presence of more parents allows for greater diversification of labor. Many parents may prefer having a stay-at-home or homeschooling parent, but see a second working parent as a necessity. With more parents, there are more possible arrangements (e.g., 1 stay-at-home parent with 3 working or 3 stay-at-home parents with 5 working).
Having more parents also enables a wider diversification of parental duties. Parents could do household chores or errands that they are especially good at or prefer (e.g., cooking, cleaning, shopping, driving, coaching, etc.).
Diversification and pooling of resources tend to be more efficient, enabling more children or a higher quality of living. When more people live in the same household, it is more affordable to have a larger home.
This would enable larger families in a world in which fewer people are in close proximity to their extended relatives and have fewer siblings. The benefits of having more loved ones are likely substantial.
Perhaps most importantly, people could have biological offspring that will benefit from Iterated Embryo Selection, making them more likely to be healthy and successful. Selection for emotional stability and prosociality will likely result in the positive outcomes of being easier to parent and a nicer sibling.
While unrelated individuals could also consider some of these arrangements, they are likely less appealing and practical without a shared genetic interest. When people are biologically related, they feel closer. Although multiplex parents may know that they are less related than a normal parent, they may not feel it on an emotional level and still maintain bonds typical of a 50%-related biological parent.
In a world with reproductive autonomy, people will explore the possibilities, with at least some trying multiplex parenting arrangements. This could be especially appealing to polyamorous couples. Pro-natalists could see this as a positive model for increasing fertility and increasing one’s genetic contribution to the world, although through unusual means.
While the concept of multiplex parenting may seem unconventional, many people are already accustomed to step-parents, step-siblings, half-siblings, and adopted children. And people already live in close proximity to grandparents, nieces, nephews, and cousins. Some people even have two same-sex parents. Anyone concerned about less attention in parenting arrangements would be wise to instead focus on single-parent households. Multiplex parenting seems less problematic than many of the most common family arrangements. Perhaps it would be considered as not too unusual within decades of adoption.
good post, friend.
Would another advantage of multiple gametic parents be less reversion to the mean? With just two extraordinary-on-some-measure people contributing, it's presumably more likely to revert to mean and have less extraordinary offspring, but I'm having a hard time imagining how the recombination would actually work with 16 or 64 contributors. I'm essentially thinking of it like randomly shuffling amongst the contributors.
I imagine it would then have to depend on the direct lineages of all the contributors - if they're from standout families like the Darwins, Wedgewoods, Galtons, Mills, etc, they're less likely to revert to the mean, due to having less randomly "up" components in their genomes, but if they're from less distinguished lines on whatever measure, more of their extraordinary trait will have been driven by randomness rather than substance. But I'd expect familial accomplishment to be basically randomly distributed in a group vs 2 people too, unless there's an explicit selection effect for distinguished lineages. So maybe the same risk / tendency for mean reversion. What do you think?
Time for some of the extraordinary familial descendants of the world to step up, form polycules, and create some uberkinders!
More realistically, if this is ever a thing it will be via uterine replicators + government selected pools of contributors to make the uberkinder.