I think people are becoming more accepting of incest and these programs get people talking about it. Incest has been around for a long time and many people have experienced incest one or another, Whether its kissing or intercourse. I think if adults use birth control and its consensual then it is absolutely fine to have sex with a family member.
The more often that particular scenarios and topics are repeatedly played out before us the less that they have the ability to shock us. I obviously do not believe that much people will change their morals after watching a show and I certainly do not believe that seeing such things on television will encourage anyone to engage in such activity. However, I do believe that with watching shows which depicts such relationships, we can sympathise and relate to characters plight in one way or another. We may also romanticise these relationships even though we are aware that they are wrong, and we may make excuses for them and thus our condemnation of such a taboo subject becomes a circumstantial one and the issue no longer seems as black and white as it once did.