There’s a Hank Green video somewhere where he explains why developing a sperm and egg from the same person’s stem cells and fertilizing the egg with the sperm would be horrifying. As far as I remember, it’s less about the presence of extra chromosomes and more about the sheer amount of information that would be lost. But I assume that the existence of cloning already implies a way to get around this problem.

in the book I'm writing, one alien species solved the extinction risks of managing low population counts in long-separated populations. An example scenario would be, what if 50 members of the species left the galaxy to do crime or weed in another galaxy, then their home galaxy unexpectedly got destroyed. If humans encountered this scenario, and no living populations of humans had more than 500 members, extinction within 1000 years is basically guaranteed. But really, do you want to travel to a galaxy with over 500 other people? Maybe you'd like to go by yourself or with only your parents or three friends. It might not be possible to return home then ask more people to come back with you if you find a great place to hang out so far away.

Anyways, they solved this by genetically engineering themselves so that each individual will have the genetic diversity of 2 million individuals with legacy reproductive organs, in addition to the other obvious genetic engineering ideas like no cancer and live longer. Thus, a single member of the species can perform a sexual construction of a fetus and birth without the historically required partner or external birthing hardware like hospitals.