Children are children. Is this sentence correct? [closed]

Sentences of the form "Something is something", where both instances of "something" are replaced by "money", "food", or any other everyday object, is something of an idiom meaning that the named object is mundane and instances of it are, in some sense, interchangeable.

"Something will be something", with "something" replaced, eg, with "children", "politicians", "neighbors", et al, is a somewhat different idiom meaning that the named individuals will tend behave in a fashion consistent with their ilk, whatever that may imply.

In particular, "Children will be children" is sometimes applied to adults behaving in what is perceived to be a childish fashion.