If they are told the truth, they will naturally be repelled.
We raised our kids as sheltered as one can at this time. We never talked about homosexuals or anything like that. When he was in 5th grade our oldest went on a class trip to go whale watching off Cape Cod. On the day before they were to go out they had a cook out on the beach where he saw two homosexual men walking hand in hand and kissing. He said that he was so grossed out he couldn't eat. This may be the only meal he has missed in 19 years. LOL