Leviticus 20:23

And ye shall not walk in the manners of the nation which I cast out before you, the nation of the Canaanites with all its branches; for they committed all these things, and therefore I abhorred them. This implies that the sins enumerated in the list above were offenses against the natural law, against the summary of God's will as it was implanted in the hearts of men at the beginning. They were unnatural sins and vices.