There certainly are religious influences in culture and vice versa. In some cultures they are identical. And sometimes those can be teased apart, or at least the reasons for some biases be assigned.

The cultural inhibitions re incest seem to have a sound biological basis which may have been discovered by each culture. Or as a part of developing sexual reproduction incest may have been discriminated against. And homosexuality seems to be similarly discriminated against, but like you I don't know why.

Something more similar may be slavery and women's sufferage. Slavery was a cultural matter which was accepted by religions, as was the effective ownership of women. Both of those have changed with time, though I'm absolutely convinced that someone who was raised with slavery could well believe it was right, just and moral. And that women's sufferage, something which now seems obvious to Americans, had to come along slowly, too.

Looking at how far gays have come in societal acceptance in my lifetime I'm sure in another generation they will be largely integrated. And as the genetic basis is more fully explored people will realize they don't have to fear proselytization of their children. I'm aware there are bisexual people, but they seem to find willing partners without forcing some violations of a partner's sexual inclinations.

(The two women in your church may well have regarded themselves as "married" and legal or religious sanctions not have been necessary to force them to stay in the relationship. However, for matters such as health insurance, Social Security, even hospital visitations they were SOL.)

I'm not sure what the difference between "marriage" and a "civil union" may be as a legal matter. I'm aware there are religious differences.

Arf