Are Catholics Christians?

Are Catholics Christian? If the Roman church denies what we might view 'key doctrines,' does this mean every Catholic lacks faith?

But what about evangelicals? In some countries like Brazil, Catholics seem to hold a stronger line on marriage than the evangelical charismatics!
So who are the true Christians here?

Unity is commanded by Christ, but what does he mean by that? Did He want a unity that was merely institutional? Or a unity that began with love within the heart? Which brings us to the practical question - how do we teach our children to view the church down the block from us, a church that may hold different views than us?