[Noor 24:21] O People who Believe! Do not follow the footsteps of the devil; and whoever follows the footsteps of the devil – so he will only bid the indecent and the evil; and were it not for Allah’s munificence and His mercy upon you, none of you would ever become pure – but Allah purifies whomever He wills; and Allah is All Hearing, All Knowing.
[Noor 24:58] O People who Believe! The slaves you possess and those among you who have not attained adulthood, must seek your permission on three occasions; before the dawn prayer, and when you remove your garments in the afternoon, and after the night prayer; these three times are of privacy for you; other than these three times, it is no sin for you or for them; moving about around you and among each other; and this is how Allah explains the verses for you; and Allah is All Knowing, Wise.
[Noor 24:59] And when the boys among you reach adulthood, then they too must seek permission like those before them had sought; this is how Allah explains His verses for you; and Allah is All Knowing, Wise.
God is clear. How can such words as above may not be clear? 'normal' relations between family members, which can lead to incest is more than just Zina is an absolute disgrace and an ordeal for anyone who has experienced such a thing. Lifelong psychological damage is the result. And I know whereof I speak. Sorry, but please read the Qur'an properly. Thank you.