Smallest crew required for a multigenerational trip to Proxima Centauri

This analysis assumes conventional reproduction, which is probably just as interesting in the context of general population studies; when it comes to dealing with the issues in space travel, however, there would be a number of options for dealing with genetic diversity (possibly even without relying on any significant advances in biotech). For example, you could send along a large sample of genetic material (gametes or fertilized eggs, for instance) taken from a broader swath of the population. In that case, I'd be curious about the sociological and psychological consequences of a group in which children might never be genetically related to their parents.

A more science-fictiony approach might be to simulate genetic combinations and synthesize resulting embryos. You could start with the actual parents, pairing their genes with a database of outside contributions for an arbitrary number of generations. In effect, you could give birth to a distant descendent.

I think the fertility issues could present bigger challenge, possibly requiring a technological assist. And when the simulated catastrophe hits, I suppose it's time to spin up the spare incubators and get ready for some sleepless "nights".

On a side note, I thought it was amusing their inbreeding calculations included identical twins. Maybe that was just to establish a theoretical limit.