Zig Zagged: The spell is imperfect, so Mike keeps turning into Michelle or back to Mike at random intervals, generally using the Rule of Funny. Whether it affects him physically or mentally as well seems to keep going back and forth—there's evidence for both.
Averted: Although there are transformation powers or gadgets in the setting, no one ever changes gender.
Enforced: The story was written for a TG fiction site, and wouldn't have been accepted if there weren't gender-bending in there somewhere.
Lampshaded: "Huh, an ancient two-faced statue marked with the combined male and female symbols. I don't like where this is headed."
Invoked: Marcy specifically studies a spell for just such a purpose.
Exploited: The heroes are up against a monster and its powers don't work on women. As the team has no women, the mage turns warrior Mike into Michelle to battle the creature.
Defied: "Foolish witch! I am carrying the sacred herb moly, which protects me from all transformation magic. Did you really think I didn't see that coming?"
Discussed: " 'Turn him into a woman!' That's your answer for everything, isn't it?"
Conversed: "How long do you think it will be before the first Gender Bender incident in this new anime sitcom?"
The story downplays the fetishistic elements of the change, instead concentrating on the mundane details of proving your identity after a transformation, getting all your paperwork updated, avoiding becoming a scientific lab study, and dealing with the fallout of all your relationships. If in full detail, examines the effects of a massive, sudden shift in hormones and how it affects how someone thinks and acts.
Mike/Michelle can't take being the opposite gender and is driven insane and/or kills him/herself.
A Wizard Did It! The reality-bending aspect of the transformation smooths over any boring mundane nitpicks, so the writer can get back to the glorious Fetish Fuel.
Guy turns into a girl, and can enjoy the fact that now people pay attention to her feelings, are way more reluctant to hit her, and can now act on what is often considered feminine behavior without being ridiculed for it. The paperwork may be way weird, but still less extensive and complicated as the one necessary for the sexual reassignment surgery she had been saving money for.
Played For Drama: The story focuses on Mike's hatred of his new form and inability to cope with a woman's social role, in a metaphor for real-life gender dysphoria. Michelle faces gender discrimination both subtle and blatant, sexual harrassment, and alienation from her friends and family, who don't accept her as the same person.
Go back to Gender Bender here, sir- I mean ma'am- I mean... Just... Just go, already!