Personally I find incest relatively amusing. Especially in Genesis - which is a word of the same root as genitals, (pro)genitor... et cetera.
If Genesis is to be taken literally as the inerrant word of the Deity, then there is no escaping the fact of brother/sister sexual relations. Or even mother/son, or father daughter.
The Noachic story implies first cousing sexual activity too. There is simply no avoiding the issue if the Bible is to be taken literally.
This raises the interesting question: at what point did incest cease to be OK? Where in the Bible does it say that there shall be no more incest as it is sinful? I have never come across it in Genesis. Leviticus, referring to a time much later than the supposed time of Genesis does make prescription, but after how many thousands of years - about 3,600, if we take a creationist timeline. Rather late in the day, no?
To take the early part of the Bible as historical, in the context of it being the inerrant word of God is against reason and therefore cannot be regarded as holy or sane. It requires mental contortions to accept that God allows what is later condemned as sin, thus making the Deity into a changing and whimsical being. So much for 'O Thou that changest not...' It is saner and reasonable to regard Genesis as man's attempt to approach his own existence and how he came into being. his sense of the transcendent and his relationship to it by use of allegory. This in no wise violates the creator role of any Deity. Rather it freely admits that things have happened of which the human species has only the most limited understanding, and towards which humans will ever strive to understand more fully.
To recede into the cosy error of Biblical inerrancy and foundationless claims of creationism is obscurantism and stupidity that fly in the face of the Deity by denying the intelligence that raises humanity above the level of the beast.