Muslims. By the concept of 'Born Sinners', the Christian say that everyone is born with the sins inherited -?

As far as I can tell, Christians don't believe in inherited sin. The concept of being "born in sin" or "born sinners" is just that they believe you're a sinner until you're a Christian, but they don't think babies are culpable, so I don't really understand why they use that phrase either. It only makes sense to them.