I'm surprised that this hasn't been a topic yet; has there or could there ever be a female playing Mary Sunshine (besides in the 2003 film)? I personally don't see why there couldn't be; all you would need is to be a Soprano 1.

In the current Finnish production there is a female Mary Sunshine. I didn't like the change too much but I guess it's okay if you don't know the character being a man in other productions.
Then again, the Finnish production was a bit of a mess anyways, besides the gender reversal it had removed Hot Honey Rag and changed lines with no apparent reason...

Isn't it kinda a plot point that "she" turns out to be a man in drag?

Not to mention that there are precious few roles for counter-tenors in musical theatre.

Why not cast a man in the role?

The production I'm in right now has Mary Sunshine being played by a girl.

The major problem with this is that changing the gender of a character is a violation of the contract that a production company signs when purchasing the rights to perform the show. The choice to make Mary Sunshine female not only derails a plot point in the show (as has been mentioned above), but also clearly goes against the intention of the creators in their choice to use a character in drag as a symbol that builds into the show's themes and satirical commentary.

Not untrue. But if this is the case, then why do the show at a high school at all? As RJ mentioned, it's wrong to cast a girl as Mary Sunshine. If you have to cast a boy, and there is no boy who can ably perform the role, then do another show.

That's not what I said. I said that a high school shouldn't do it if there is no male performer who can play Mary Sunshine. If there is, then I say go for it.