That played a switch in roles. Like, " Just One of the Girls" seems like a spin-off of "Just one of the Boys," starring Corey Haim.
More like the other way around.
Just One of the Guys
was released in 1985 and
Just One of the Girls
was a 1993 direct-to-video, originally titled
Anything for Love
.
Re gender-bender movies: There's also 2002's
Juwanna Mann
, about a disgraced NBA all-star who infiltrates the WNBA incognito, in order to get another chance to play professionally.
.

Like Father Like Son with Dudley Moore and Kirk Cameron

Willy/Milly (aka Something Special) is another good one. Came out a year after Just One of the Guys.

Yeah, it's a common trope, and not just in the 80s & 90s Off the top of my head:
First, you got the supernatural body swapping movies, like:
18 Again (grandfather/grandson)
Freaky Friday (and the remakes - mother/daughter)
Vice Versa (father/son)
It's a boy/girl thing (boy/girl)
The Change-Up (friends)
The Hot Chick (boy/girl)
Dating the enemy (boyfriend/girlfriend)
Dream a Little Dream (boy/man)
Wish Upon a Star (sisters)
Prelude to a kiss (man/woman)
and then there are similar movies that swap characters for their younger/older selves like
17 Again
13 going on 30
Big
and then some drag movies like
Tootsie
Mrs. Doubtfire
She's the man
Just one of the guys
Just one of the girls (Anything for love)
Ladybugs
Sorority Boys
and finally, there are other, non-supernatural swaps, like
Trading Places (rich/poor)
Soul Man (black/white)
I'm sure there are many more, but those are the ones I'm aware of.

Freaky Friday.

Awesome 90s movie based on switched roles, Little Sister. http://www.imdb.com/board/10104741/?ref_=fn_al_tt_2
By the way, the Corey Haim movie was called Just One Of The Girls.