If the Catholic Church wants to prevent sexual abuse by priests, several abuse experts said, there are better ways to do it than by trying to bar gay men from the clergy. The church recently began checking American seminaries for ''evidence of homosexuality," and the pope is widely expected to ban actively gay men from taking holy orders. But it will be tricky to cull gays from the priesthood, the abuse experts said this month. And it would be more effective -- and more humane -- to target likely abusers rather than all gays. ''There's no adequate way to screen...