Why does incest happen?

"I was very confused about what was happening."

As it's revealed a mother and her son in Michigan, US are in a sexual relationship, we find out what triggers such behaviour. Natasha Rose Chenier, the author of memoir Salt, describes the relationship she embarked on with her long-lost father after they met. Psychologist Corinne Sweet then explains why this is not all that unusual.

(Photo: Illustration of Natasha Rose Chenier Credit: Val McBain )