Boys will be girls
Where does the phrase "boys will be girls" come from?
"Boys will be boys" is the only saying I know to be in general use, Eammon. Ray Davies, though, has the line:
Girls will be boys, and boys will be girls
It's a mixed up, muddled up, shook up world
in his classic song, 'Lola'.
Could this be what you're thinking of?