Walt--

My daughter had an interesting idea. I suppose she's rather more prudish than I, being only 13, but she's managed to maintain careful marital fidelity among all her villagers. Nobody gets to breed unless they're paired up on her scratch-paper marriage registry, and nobody gets to pair up with a sibling or first cousin, either.

Most players aren't going to want to invest this kind of energy tracking their births (and pausing the game so as to monitor who goes indoors!) . . . but you might want to hide a nice treat for anyone whose village children aren't inbred after a few generations! (Or maybe even just make the villagers refuse to breed with their siblings?)

Btw . . . she does allow widows to remarry. Generous of her!

(Some example I am. My villagers breed with whomever's handiest when I decide to encourage more babies. I've even managed to get eight of them in that hut at a time, which absolutely horrifies my poor daughter!)