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For whatsoever man he be that hath a blemish, he shall not approach: a blind man, or a lame, or he that hath a flat nose, or any thing superfluous. 21:18
Notice that in this long list of relatives that you may not have sex with, there is one relative that is not mentioned -- your daughter. Nowhere in this list, or anywhere else in the bible, is sex between a man and his daughter (or, more generally, between parent and child) forbidden. 18:6-18, 20