No, it is not "immoral", the words "moral" and "immoral" are just words generally used in our culture to say certain behaviours are "good" or "bad" that should or shouldn't be done with little or no reason/explanation put forth as to why it is.
That said, it can be extremely damaging to the parent/offspring relationship, I would think that a parent that would trade the special (non-sexual) relationship that parents and offspring generally share with each other in exchange for a "sexual" one would be a fool (there are a lot of other people to have sex with)- Immoral no, foolish in the what could be given up, yes./QUOTE]
Good point; I have however seen the 'Trap' that I had not seen before' in that if the incestuous relationship is with a parent (ie a male of female role model) the psychological effect on the young person willl most likely lead to sexual problems at a later date (ie not being able to form relationships etc)