Flashback to the Language/Gender Wars
In languages that distinguish between the informal second person and the formal second person (like French and Spanish) 'girl' correlates pretty closely with the informal second person. You can pretty much 'tu' anyone you can call a girl. You can use the term 'girl' informally with adult human women. 'Tuesday is girl's night.'
You can talk about girl power. There's a formal term 'manpower'. But 'woman power' and 'boy power' don't seem to work in English.
Before I could go any farther than that, I fell asleep.