I'm not familiar with the "brethren" of whom you speak, but it's not surprising you haven't heard the term from mormons.
However, among Protestant Christians it is not a new or colloquial term as has been posted by others far more eloquent than I.
The mormons are concerned with getting their own planet, the papists worship idols and ask for confession from pedos.
Being born again and taking responsibility for your actions is a different thing.
