Visual novels and similar games with young (looking) characters tend to get rejected for sexualizing those characters (rule 8). But there are also plenty of examples of tame games getting rejected, while similar but much more risque games were permitted, so it's hard to figure out exactly what Valve objects to.
https://partner.steamgames.com/doc/gettingstarted/onboarding...
Visual novels and similar games with young (looking) characters tend to get rejected for sexualizing those characters (rule 8). But there are also plenty of examples of tame games getting rejected, while similar but much more risque games were permitted, so it's hard to figure out exactly what Valve objects to.