Historically, going back centuries, many (but not all!) Conservatives have been Christian. But you do not NEED to be Christian to be a Conservative. But historically, even those thinkers who did not actually believe in the Judeo-Christian faith, if they were Conservatives, they still saw the value in the moral rules laid down in the Bible.
Individuals, families, and society benefit from these moral precepts. Even if you don't share the faith, you can see that these social rules have value.
And therefore, faith or not, there should be no question of "evolving".
Homosexuality is wrong. Always has been. Always will be. People who "evolve" on the issue are utterly missing the entire point of what Conservatism is all about. It's about a moral code which is above mere human whim.
Dennis Prager did a great article on this:
Judaism’s Sexual Revolution: Why Judaism (and then Christianity) Rejected Homosexuality
http://www.freerepublic.com/focus/news/3292085/posts?page=5
Exactly. It robs the word conservative of any true meaning.