The Windows 8 Store won't be stocking any games rated PEGI 18 or any apps with any kind of adult content.
Microsoft's Windows 8 app certification requirements are pretty clear on the matter, classifying 'Adult content' as anything rated PEGI 18, and specifically stating that "Adult content is not allowed in the store".
This doesn't mean you won't be able to play the likes of Skyrim on Windows 8, just that you'll have to get hold of it through other shop-fronts (like Steam).
Or you could go old school and buy a physical copy – don't forget your ID.
Apple caused controversy when it prudishly pruned thousands of sex-related apps from its iOS App Store back in 2010.
But it looks like Microsoft won't even be letting these risqué applications into its shop in the first place.