I find it interesting that Kirk Cameron's recent remarks about gay and lesbian marriage were described as "even more outdated than his 1980's TV character" by GLAAD Senior Director of Programs Herndon Graddick.
Outdated or not, it seems to me that Kirk was being honest about his beliefs, and his First Amendment rights shouldn't be any less important that those of "a growing majority of Americans" who find his views contrary to theirs.
In John 13:34-35 (NIV), Jesus says "A new command I give you: Love one another. As I have loved you, so you must love one another. By this everyone will know that you are my disciples, if you love one another."
It seems to me that you can love one another without supporting same-sex marriage.