@xenmen @applejack @LouisConde If people just had enough dang kids, incest wouldn't even be in the cards at all. It's a testament to how isolated, how sparsely populated, how starving for intimacy, and how sexualized young'uns are now. It's just a rich, awful gumbo pot only brewable in crumbling shantytown civilizations.
He might be in favor of the courtwhip/chaperone system, and thinks you should never be alone with someone of the opposite sex. Then his position is consistent at least, you really wouldn't be doing anything remotely intimate with your gf.
He probably doesn't have siblings either. I recall "wincest" being quite a fetish in the USA among single-child guys 15 years back....