Their mother took it a little badly, didn't she?
I thought the scene in which she discovers them having sex was way over the top. The movie was clearly hoping to hang all its critical plaudits on this scene but I thought it was totally overacted.
To be honest, the movie as a whole was a very opportunistic depiction of incest. It didn't try to get behind Jere or Meme's mentality or to really explain the nature of their emotions towards one another. Incest was simply presented as yet another calamitous horror-story that can strike at the heart of middle-class domesticity. Proper dialogue was severely lacking throughout. The film hoped to garner acclaim for its controversial subject matter alone, and furthermore that its audience would overlook a spare story and flat characterisation.