There was a coffee shop (or was it a bar?) that I remember going to in college. In the bathroom was a collection of clever graffiti scrawled on the wall. Nothing too profane (per my admittedly questionable recall) but lots of pithy expressions. I remember one quote I found funny written in neat print, "Insanity is hereditary: you get it from your kids". I didn't have kids at the time but it still struck me as funny because: A) Heredity doesn't work like that - you would get insanity from your parents - and B) It sounds pretty plausible until you pause and bring your knowledge of genetics to the subject. The juxtaposition between A&B strikes me as its likely source of mirth although when you diagram mirth it tends to dissipate fast.
But with epigenetic ideas in the picture, do we need to rethink whether this statement is simply false? Could, in fact, dormant insanity (putting aside any Foucaultian critique of the notion) acted on by an environmental trigger (kids) lead to some sort of encoded/ hormonal/ neural cascade that leads to insanity in behavior? And could I then be said to inherit that from my kids? Could that patten, an environmental trigger introduced by kids on parents be repeated across generations? Could subsequent children borne to a parent already triggered through an earlier child inherit that insanity through epigenetic silencing/activation of gene sequences?
I don’t mean to be anti-kid here. By this reasoning one could also inherit joy from children (and in fact I think one does). I am merely making the point that inheritance may not simply be just what one gets from one's ancestors.