Incest is also based on dominance, though, at least it certainly is between a parent and child. LKH's fetish for young men and boys has been getting worse over time; first it was Nathaniel, then Cynric, and now we have Matthew being groomed by Nathaniel. The relationships between Anita and her dildos are always parent/child; either she parents them (reading to Nathaniel at night, going to Cynric's PTA meetings) or they parent her (dressing her, feeding her). Maybe that's why Richard and Asher keep getting shat on, because she can't stretch their kinks to that. LKH doesn't have a son of her own, so I don't think she'd see mother/son as bumping against her own life.