The Red Queen hypothesis for sex is simple: Sex is needed to fight disease. Diseases specialize in breaking into cells, either to eat them, as fungi and bacteria do, or, like viruses, to subvert their genetic machinery for the purpose of making new viruses. To do that they use protein molecules that bind to other molecules on cell surfaces. The arms races between parasites and their hosts are all about these binding proteins. Parasites invent new keys; hosts change the locks. For if one lock is common in one generation, the key that fits it will spread like wildfire. So you can be sure that it is the very lock not to have a few generations later. According to the Red Queen hypothesis, sexual reproduction persists because it enables host species to evolve new genetic defenses against parasites that attempt to live off them.
Sky & Telescope illustration. During my search it hadn't occurred to me that radio might have played a role. My newspaper column had just gone to the printer when I got a copy of the December 1990 Astronomy. There, Deborah Byrd mentioned the term coming from a March 1946 article in Sky & Telescope (page 3). (But S&T had got it wrong, too !) Contacting her, I found out she had read it for her National Public Radio program, Star Date, in late January 1980. No doubt that's where the authors of the children's almanac heard it. Clearly, Byrd's radio broadcast got the recent "blue Moon" ball rolling.