Not with many local non-discrimination laws like the ones here. Homos are treated as special protected victim status the same as blacks, in the laws.
I know I posted this on another thread, but it bears repeating.
Discuss it with a lawyer first, but as near as I can tell a church can legally discriminate. It has to be a clearly written policy that cites scripture, but it can be done.
And like I said previously, I have not seen this tested in a court of law. Frankly I think it would be interesting to see.