There's a lot of terminology, like "washes whiter than snow," and these things which when they're said in a uniracial congregation, they just go fine. But when they're said in a mixed congregation, some people will get offended and wonder, "Why are you saying that? What are you saying?"

I spent a lot of time developing in books why worshipping separately actually impacts inequality, economic, social, on and on. So I really do believe there are huge advantages to being together even though it's difficult, even though we have a lot to learn.

I think it's pretty dynamic. There's a lot of energy there and life, and you'll have women dressed in their traditional African dress when they come, and you have people from all over the place, and some people have headphones on because they're listening in Spanish.

We do not have an American culture. We have a white American culture and a black American culture. So when those two groups try to get together, [it's] very difficult because they each feel like they have the right to their culture.

One of the things we find when we talk to people that attend these congregations, they all have social cost to it. People want to know why they're doing that. Sometimes they're questions about selling out on their race or "Are we not good enough that you have to go to this kind of congregation and not ours?" So there are costs to it, and I think they're a little bit higher in the South because of its history.

I see it happen in uniracial congregations all the time. But people - when they're in mixed company, we speak differently.

There's one denomination in particular, though, that has pushed very hard to be multiracial in its denomination - not only its denomination but, I mean, in its congregations, and it's called the Evangelical Covenant Church, http://www.covchurch.org/ which is headquartered in Chicago. Their whole goal is that's the kind of churches they start, multiracial, and I think they say now 20 percent of their churches are that.