This will disgust the more moon-goddessy type feminists and please the "it's all about choice" ones. For everyone else, after a while, it will just seem, well, natural.
You also asked, very reasonably, why the couple in the original letter (she wanted to take something to suppress her periods so they could have romantic weekends) couldn't just have sex, blood or no blood. The answer is they could, of course. I'm willing to bet that they hadn't even discussed and dismissed that option, as "no sex when the painters are in" is just one of those things everybody takes on faith until they don't. If a woman's "monthlies" turn out to be at least partly a social invention, the menstrual taboo is entirely one. Barring the presence of something nasty, blood-borne, and contagious, there's no reason on earth (or the moon, for that matter, and aren't we going back soon?) why a couple can't have a threesome with him, her, and Aunt Flo.
Speaking of the moon: women down here have connected their sexuality and fertility with the phases and pull of our satellite for so long that I have to wonder what happens to all that lunar blood magic when we're living in bubbles on the moon. Nothing takes the mystery out of a hunk of rock and dust like having to dig holes in it to build a privy.
Andrea Nemerson has spent the last 14 years as a sex educator and an instructor of sex educators. In her previous life she was a prop designer. And she just gave birth to twins, so she's one bad mother of a sex adviser. Visit www.altsexcolumn.com to view her previous columns.