The fermi paradox asks the question of why we don't see intelligent life when we look out to the stars. Various explanations involve the improbability of life developing to the point of a space-faring interstellar civilization. Since we know that one species developed to our level of technology--us--it's likely that whatever hurdle aliens face is still ahead of us. The explanation I'm proposing here is that genetic engineering gets developed prior to interstellar travel, wiping out the species before it had a chance to spread. It's not a great explanation, but all the other ones aren't that great either.

Woah man, but like, if the young people weren't really humans, and the old people were, it's like first contact