Any gender bent character will either embrace or be subject to all of the stereotypes associated with their new gender.
Characters who change gender will adopt "gender appropriate" dress and behavior. The fact that this typically means dresses and makeup for a man turned woman and aggressive, macho behavior for a woman turned man makes this trope rife with Unfortunate Implications. Frequently rationalized as being due to the characters having stereotypical views of gender roles, particularly when the character in question is depicted as being in need of a gender equality lesson.
Like the second law, this trope typically manifests in one of two forms:
A masquerade wherein the character is forced by circumstances to adopt stereotypically masculine or feminine attire or behavior, sometimes under duress. (This is especially the case in Freaky Friday Flip plots or other situations when the character becomes a preexisting person of the opposite gender, and must therefore keep up whatever stereotypical behaviors they actually did.)
More sophisticated applications of this trope will often try to find common ground somewhere between these two extremes. It may be as simple as characters wanting or needing to be treated "like a normal person" and thus adopting stereotypically "gender appropriate" attire and/or behavior to conform with their perception of the new roles they've been forced to adopt.
Since most gender benders are male-to-female this frequently results in scenes where the newly minted "girl" is confronted with all of the "requirements" of his new gender, which can include skirts, hose, makeup, high heels and other trappings of femininity which, while common, are by no means mandatory in real life.
This frequently results in a Family Unfriendly Aesop reinforcing stereotypical behavior, and some people may find the notion of underlying biological imperatives enforcing such behavior deeply offensive. May result in Becoming the Mask or Going Native depending upon surrounding circumstances. Often precedes the Second Law of Gender Bending which may stem from this trope, and may result in a Shopping Montage and/or Makeover Montage as the new boy or girl (willingly or not) gets "geared up" for life in their new gender.
A mild version can be found in The Day Of Revolution: Megumi is not shown wearing any exclusively female clothing outside of her girls' school uniform, but since it is Japan her uniform has to be a stereotypical Sailor Fuku complete with a ridiculously short skirt. She also has her coach/therapist/BFF Motoko constantly reminding her to act more like a girl. Presumably she only puts up with this because she actually wants to be a girl, she's just riddled with second thoughts and self-doubts whenever she confronts one of the disconcerting aspects of girlhood.
Motoko (looming over a prostrate Megumi): ...sooner or later, you're going to be looking up at someone like this.
Played with in Ranma ½: Ranma's actions are typically the same regardless of his form, but his reactions are often stereotypical, especially in responses to "perverted" behavior from the likes of Kuno or Happousai. In those cases his reactions usually differ very little from any of the real girls in the series. Also, whenever Ranma is in "disguise" as a female he typically overdoes it, implying that he's consciously trying to act out stereotypes. When he hits his head in one episode and thinks he was always a girl, he becomes the epitome of this trope.
Heavens Lost Property: Tomoki will occasionally use a special device to turn himself into Tomoko so (s)he can act out various shoujo tropes.
Tenshi Na Konamaiki: For all of her insistence that she's truly a boy Megumi shows little male behaviour besides aggressiveness.
In The World God Only Knows, during a Freaky Friday Flip, we see The Protagonist start leaning to the "dark side of gaming" ( playing Dating Sims... for girls!) and behaving more and more feminine (thanks partly to the Weiss that initiated the flip). We also see the girl he switched with start acting more like a boy, although in her case it's largely down to the Masquerade of maintaining his life. Later on in the story however, she becomes a Bifauxen because she is comfier looking and dressing up as a guy.
An extremely subtle example in Vandread: the character that displays the most blatantly Femme Fatale/Lady of War body language is eventually revealed to be a gender-bent mole. She often looks like she's posing like a runway model because that's exactly what she's doing.
In All of Me, while the heroine is technically sharing a body with the male protagonist, when he falls "asleep" during a court scene, she has to pretend to be him during a cross examination. Her attempts to act male include, but are not limited to, widening her shoulders as much as possible, deepening her voice to ridiculous extents, and even pausing to spit into a non-existent spittoon.
Jack Chalker's River Of Dancing Gods series literally has variation 2 written right into the physical laws of its universe. The one character who resists is desperately unhappy.
Despite being a serial Gender Bender herself, Hildy Johnson, the protagonist of John Varley's Steel Beach insists that there are still "girl things" and "boy things" when it comes to dress and behavior, because otherwise there would be little point in changing gender in the first place. This serves to underscore that Easy Sex Change has become so easy in Hildy's world (you can get a sex change in a beauty shop or a tattoo parlor) that some people are willing to change sex just to facilitate a relationship or even just to suit their clothes.
Initially played straight in Justin Lieber's Beyond Rejection as required by a masquerade; justified later when it's revealed that the "masquerade" was actually part of an artificially-induced therapeutic dream intended to enable the protagonist to adapt to an involuntary Gender Bender.
Virginia Woolf had...strong but hard to codify opinions about gender expression, but they result in Orlando getting very feminine 'naturally' after his/her genderbend.
After leaving the gypsies, of course. Which is a research goof, since the Rom tend to have serious taboos associated with womanhood, and a Romany encampment is not the best place to be if you're menstruating for the first time at thirty.
The Marvelous Land of Oz: After Tip is turned back into Princess Ozma, he instantly transforms from a fairly rambunctious boy to an exceedingly Girly Girl. However, given the date of publication (1903) it's highly unlikely anything else would have been considered acceptable.
While this can be handwaved by saying "a sorceress did it" (not that the rest of the Oz magic made any sense), Fan Fic occasionally deconstructs this by establishing that Tip is still Tip and the Ozma personality is just a mask put on for the sake of the people.
Later writers in the Oz Mythos have also addressed this question in novels and short stories, including The Disenchanted Princess of Oz by Melody Grandy, The Mysterious Chronicles of Oz by Onyx Madden, and Ozma Sees Herself by Edward Einhorn. These works all take advantage of the apparent time gap between The Marvelous Land of Oz and Ozma of Oz to insert an interquel that covers Ozma coming to terms with her transformation.
The Wonderful Wizard of Oz Anime adaptation, on the other hand, takes a pragmatic approach by depicting Ozma as a rambunctious Tomboy Princess, allowing her to be a genuine girl (Tomboy is just another aspect of the feminine, after all) without the unsettling Loss of Identity implications of the original.
Finally, the recent Marvel Comics graphic versions of the novels take advantage of the graphic format to deconstruct this trope a bit within the art while the script hews closely to the original text. Some of Ozma's expressions are just priceless.
Piers Anthony's works frequently include gender bending, usually accompanied by this trope. He tends to write natural laws into his settings which force certain behaviors and responses onto characters based on their physical sexes. Several of his books also combine this with I'm a Man, I Can't Help It. A female will turn into a male and learn that males are such virile creatures possessed with such strong libido they must constantly struggle to contain those urges and not turn into rapists. Some specific examples:
In Incarnations of Immortality... and Eternity, Orlene is transformed into a man and immediately becomes an aggressive, misogynistic, testosterone-charged boor, attempting to rape her friend Jolie. Upon having her female form restored, she and Jolie are horrified and conclude that "Men have passions that women do not", and that the reason all men are not constantly overwhelmed with violent lust is that "they have learned control".
Crewel Lye in which a male character and a female one switch bodies. The former woman is overcome by hormones and can't resist planting a kiss on her old body. She concludes that men just can't help their piggish instincts, and gains new respect for the male character when she realizes how restrained he has been.
Degrassi features an inversion where Adam, after briefly and uncomfortably detransitioning, burns his last remaining girls' clothing with family and friends present.
A demi-version: Chandler, of Friends spends time quitting smoking using a hypnosis tape while he sleeps. "You are a strong, confident woman who does not need to smoke". Over the course of the episode, Chandler becomes more stereotypically feminine. He puts on chapstick like lipstick, blotting off the excess. He starts throwing like a girl. He interrupts himself to compliment Rachel on a "stunning blouse".
Of course, Chandler was metrosexual and the stunning blouse wasn't entirely out of character even before the hypnosis. "Well, don't we look pretty, all dressed up."
Gene/Jean, the supposedly male/female "transmute" in Quark: the whole transition from "Gene" to "Jean" consisted entirely of a shift from masculine stereotypical behaviors to feminine stereotypical behaviors, since no visible physical transformation actually took place.
On one episode of Star Trek: Deep Space Nine, Quark (the male Ferengi bartender) has to be surgically changed into a female Ferengi. Soon after he she completes the transformation, she finds herself taking on every stereotype of female behavior — not as part of an act, but because her new hormones now rule her psyche. (Apparently, Ferengi females are ruled by the same emotions as human females!)
In a FoxTrot story arc (playing off of The Metamorphosis), Jason dreams of waking up transformed into a girl. He panics at first, but soon experiences desires to go shopping and enjoying the Backstreet Boys. Justified, as we see that Jason has a childish view of girls (which makes sense, as he is a child).
And, he didn't know it was Backstreet Boys music until after he'd started liking it; the realization made him do a Catapult Nightmare.
El Goonish Shive has Grace's Birthday Party arc, part-masquerade where the various characters deliberately chose stereotypical outfits for each other in keeping with the 'walk a mile in my shoes' theme of the occasion.
Susan starts acting macho and aggressive immediately after becoming male. It's transient, however: losing an arm-wrestling contest with the still-female Nanase is enough to snap her out of it. Sarah points out that Susan's reaction was more her being herself, just over a different subject.
Tedd does note that the first time gender bending their new genders thoughts are exaggerated, which played a part in everyone's storyline during the event, but the only one whose gender bending mental state was a major plot point was Susan, as it helped her recognize her hangups with men.
Later, when Elliot develops the power to morph his clothes and appearance along with his gender his female forms tend to end up wearing girly outfits because he apparently just can't help visualizing them that way.
Made explicit in the case of the four Jerk Jocks who got turned into cheerleaders (The Wotch, Cheer!) where it's flat-out stated that the four primarily acted like macho jerks to repress their fundamentally kind and gentle (i.e. "feminine") inner natures
Although Cheer! does at least expand their personalities and shows that Alex retains a rather masculine love of war, guns, and battle strategies and Lita is if anything even more of a diehard gamer, which implies that Sam's and Jo's primary interests (cooking and Magical Girl anime) carried over as well. The cheerleaders in The Wotch appeared to simply be stereotypical girly-girls.
Misfile: deconstructed, along with most Gender Bender Tropes. Ash never acts or dresses like a girl beyond some minimal concessions that are either enforced biologically (periods, bras) or culturally (bathing suits, a bridesmaid dress). He doesn't hesitate to complain about it, either, in ways that make it plain it fuels his fear of assimilation, and he maintains his interest in his main "masculine" pursuits, electronic gaming and amateur street racing.
Ash's mother, however, is doing her utmost to enforce this trope, including roping Ash into a modeling event. Ash referred to seeking her help picking out a bridesmaid dress as "a deal with the powers of darkness."
The T-Girls of the Jet DreamRemix Comic, being Action Girls, retain many traditionally "masculine" traits. But because the T-Girls are often covert operatives, they have been extensively trained in all aspects of "feminine behavior." It's not purely professional, however — for the most part, the T-Girls seem to enjoy their new female roles.
Spiderwebs uses variation one: After an ill-considered wish turns the protagonist into a girl she returns home to discover her bedroom redecorated and all of her clothes replaced by a "helpful" pooka.
The Good Witch: Playing with the third law is just one of the ways Angel torments her victims. Examples include making sure all of her older brother's transformations include uber-girly clothes, turning one classmate into a cheerleader (complete with outfit) and possibly turning another into an enthusiastic transvestite. However, the third law is also played straight with Angel herself, who as a former transgendered boy is absolutely thrilled to finally be able to buy the dress she always wanted. Since she can (and does) magically create any clothing she wants at will actually buying the dress appears to have been an act of affirmation on her part.
Played with in I Dream Of A Jeanie Bottle: Jean's I Dream Of Jeannie-inspired powers means her clothing reverts to the iconic I Dream Of Jeannie harem girl outfit whenever she reverts to her base genie form and circumstances always seem to be forcing her to "girlify" her outfit even when she changes it into something else. However, she's also shown experimenting with stereotypical female outfits (Sailor Moon, Kim Possible, and Rogue) in a G-rated Man, I Feel Like a Woman sequence.
A major driving point in the furry webcomic Beyond the Veil, in which the attractive, busty young rat girl is in fact the latest body for a deposed intergalactic emperor. "She" takes to her new body very well, more than happy to have her similarly body-riding male second-in-command as a lover, with a lot of privileges.
Melissa: Fine. One date. We'll see where things go from there.
female!Kade: Squeee! You've made me such a happy guy, Melissaaa!
Melissa: If you still think of yourself as a guy, why are you wearing a dress?
female!Kade: It matched these shoes that were just to die for! And it makes my butt look cute!
Both averted and played straight in The Order of the Stick. When Roy dons the Belt of Gender Bending, he is almost immediately hit on by both the dwarf assassin sent to kill him and by Belkar (who knows it's actually Roy, but hits on him anyway to make him uncomfortable), and even Haley makes wise cracks at his expense. However, when offered the chance to either change back or stay a woman, he admits that it wasn't as bad as he'd expected going into it.
Take A Lemon actually combines variation 1 and 2: not only do the circumstances of the his Gender Bender force Marsh to adopt a masquerade it turns out his alternate universe Distaff Counterpartdoesn't own any pants as unlikely as that seems.
The Gender Bender characters of the Whateley Universe display the full range of this trope. They are expected to keep up a Hide Your Gays masquerade while at the titular school for the safety of the LGBTI students at Poe cottage, which the school justifies as a sensible precaution after an MTF student was murdered by her homophobic boyfriend. However the degree to which individual students actually participate reflects the degree to which they were (knowingly or unknowingly) transgendered before their change, the degree of their change, their degree of acceptance afterwards, and/or their confidence in their ability to defend themselves.
Chaka, Generator and Lancer (who were all transgendered before they changed) are all examples of the trope played straight.
Fey (who has a female spirit in her head helping her to become feminine) is an example of the justified version of the trope.
Bladedancer is a double subversion: She is fully female but dresses as close to boyish as she can get away with in what amounts to a Superhero School with prep school clothing rules. On the other hand, she now listens to some of the music her girlfriend Molly likes (in addition to still liking what she listened to as a boy) and appears to be gradually (if not enthusiastically) adjusting.
Fully subverted by Phase, who receives a girl's figure and proceeds to fight tooth and nail against it (despite his guardians' insistence that he embrace the change). Phase still has male genitalia and goes out of his way to announce his still-a-male-ness to everyone he meets, even though events tend to conspire to force him to pretend to be a girl. Phase's mutation got him thrown out of his Knight Templar family of Noble Bigots and Heteronormative Crusaders so it's possible he doesn't reject the change so much as he just hates himself.
Jobe Wilkins plays the biolgical imperative concept straight. He designed his current female form as a fantasy girlfriend intending to inflict it on somebody else. While Jobe still claims to want the Gender Bender reversed it's also apparent that "she" is also gradually falling prey to the biological imperatives "he" programmed into herself.
In The Fairly OddParents, when Timmy wishes to be a girl to be able to hang out with Trixie and find out what she wants, he gets the irresistible urge to watch soap operas and buy shoes.
Although he already did that first one before the gender bend, and after said gender bend he still has the urge to read comic books like "Skull Squisher". ...because of the Fanservice. "Muscular guys in spandex fighting crime, cool!"
Not actual gender bending, but in The Penguins of Madagascar, a faulty DNA test has Skipper convinced he's a female. At first he thinks it won't interfere with his job, but then he does things like wait for the others to open the door for him and - horror of horrors! - ask for directions. So he quits the team, puts on a pink bow and moves in with Marlene, who is not amused with his outdated ideas of femininity.
Sort of a Zig-Zagging Trope in Futurama, where fembot!Bender embraces his idea of what a woman should be—-basically, slutty—-but Calculon recognizes this as making her "one of the boys." Interestingly, he finds this attractive and falls in love with "her," while Bender becomes more "feminine" and worries that his scam will hurt Calculon.
In the episode "Neutopia", the guys eagerly act girly and giggly when their genders get flipped by a Sufficiently Advanced Alien. When the girls-turned-guys force them to make a swimsuit calendar, they enjoy it a lot more than the real girls did when the real guys forced them to take cheesecake pictures.
In the Jimmy Neutron Episode "Trading Faces", Jimmy and Cindy trade bodies through a freak accident and Jimmy has this start to happen him.