Girlsemanticsatiation

Yesterday's Dinosaur Comics:

Ryan arguably pushes past the bounds of good taste in the mouseover title: "girl we have some bad news on your girlsecondarycancerlabreport. i'm afraid i have some bad news for some very specific cancer girlies". But maybe that's the point?

There are certainly earlier models for the girl-NOUN (and boy-NOUN) pattern, e.g. girlfriend and boyfriend, though it's not clear why those patterns weren't used more widely. It was commoner to see girl and boy as compound heads rather than first-element modifiers: batboy, ballboy, bellboy, busboy, cowboy, fanboy, flyboy, newsboy, playboy, ?salesboy, schoolboy, ?*showboy, etc.; batgirl, ballgirl, ?bellgirl, ?busgirl, cowgirl, fangirl, flygirl, newsgirl, playgirl, salesgirl, schoolgirl, showgirl,  etc.

Just as there's an opening for more boy-NOUN coinages, the culture also obviously needs a female-gendered version of bro, in uses analogous to those featured in these panels from today's Doonesbury:

You could try "MODIFIER girls", but "MAGA girls" and "tech girls" and so on don't have the same vibe.

I've also recently been interested to hear young women sometimes using bro as a vocative tag in talking among themselves, e.g. "Why not, bro?" Among young men, such tags are now locally ubiquitous, largely replacing man. The vocative tag girl is also possible, but again, it has a different vibe.

Update — as a vocative tag, bro seems neutral or even positive among the people who use it; but the head noun is often disparaging or derogatory, as in the cited cartoon.