system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek] Why are many of the species in the Galactic quadrant humanoid and sexually compatible?

Despite evolving in completely different systems, how is it that these different species are able to reproduce without great issue?
gpt
Humanoid species largely descend from the "ancient humanoids," as found by Professor Galen on Vilmor II. The aforementioned "ancients" seeded a number of worlds with their genetic material. Thus, Humans, Vulcans, Romulans, Klingons, and even Cardassians are remote cousins.