I think it's because it is ultimately the most effective system for complex lifeforms that need to adapt to their environments. Single sex organisms do not change as readily because, by default, all their offspring are clones. Mutations obviously happen, but that can cause extinction as well as adaptation, because the mutation will automatically propagate to all future generations (because of the cloning thing.)Darth Wedgius wrote: ↑Sun May 24, 2020 9:05 pm I remembered Cochrane probably mostly because I read the Judith and Garfield Reeves-Stevens novel Federation, which brings them back for a bit, and gives Cochrane a backstory. But the novel doesn't jibe with the First Contact.
By coincidence, I'd been thinking about this episode and the whole male/female thing being universal. I used to think it was a bit of a stretch to expect that on most other worlds, but I'd been reconsidering. Of course male and female don't cover everything, but on earth male and female seem to have developed in many different ways. The X/Y thing for most mammals (I'm sure that's The Bad Touch song was talking about), the Z/W system found in birds and some reptiles, the XX/X0 system, temperature-dependent systems, etc., in a myriad of ways. Nemo's dad should have become his mother after the unfortunate predatory encounter early in the movie.
Not that the bigger critter is always the male (e.g., hyenas) or the one with the egg carries the young the whole time (seahorses), and there are species with only females (e.g., New Mexico whiptail). Obviously a species with only males isn't going to work, and not just because they'd be playing video games the whole time.
But it does seem to happen enough that there's probably a utility making it not unlikely elsewhere.
Whereas sexual reproduction allows for both natural and artificial selection, and ultimately to more intelligence (the creatures choosing their own mates).
Some Trek episodes, of course, tried to bring in a 3rd gender. But how or why would such a thing develop? There's no adaptational reason that one could successfully make. If such a thing DID manage to occur, evolution would tend to favor members of the species that adapted to do without the 3rd gender, and it would disappear over time.
The other aspects of male/female are a result of culture and nurture. Whichever parent ends up spending the most time with the young will tend toward feminine aspects, because babies are in need of that. Likewise, the "defender" of a family group will take on masculine traits to protect against predators.
So yeah... I think it's safe to say that we would discover male/female species as soon as we discover complex organisms outside Earth. Assuredly there will be differences... but there will be a lot of common ground as well.