I was flipping through Yevamos and saw that it said that the Torah does not explicitly state that one is prohibited from having relations with his daughter. I checked out the relevant passage in the Torah (Lev. 18) and found something odd.
All of the prohibitions of family relationships are phrased as "don't have relations with this woman," except for 18:7, which is the only one that prohibits a man.
You shall not uncover the nakedness of your father or the nakedness of your mother; she is your mother; you shall not uncover her nakedness.
If 18:22 prohibits homosexuality, why is the bit about the father necessary?
It can't be that it means to prohibit being with your father's wife, because that is already prohibited somewhere else (18:8).