I enjoy how many of the "nits" we know were already found by DeForest Research back in the sixties but ignored by the production staff.
True -- although there are a couple that they didn't get quite right. One, the claim that Alpha Centauri wasn't likely to have planets. We've already found one possible exoplanet around Alpha Cen B, and it's a major target star in current exoplanet searches. Two, they were right to point out that the selective breeding experiments would've had to be going on in the '60s or earlier to produce adults by the '90s, but in real life, eugenics programs seeking to breed superior humans existed as far back as the 1880s. Of course, they all defined "superior" as "white," but if there had been a program that had correctly understood that you need genetic diversity for increased fitness, and if it had continued in secret from the 1880s onward, then the fifth generation of offspring might've been born around the late '60s or early '70s, and that could hypothetically have been enough time to produce the desired results with a lot of luck. (Of course the term "genetic engineering" hadn't been coined yet in 1966, so the episode assumed the supermen were the result of a more conventional eugenics program. It wasn't until TWOK that the genetic-engineering explanation was used.)
And just think... we came this close to a movie called The Wrath of Govind