Alright, now onto gender-coding and cartoons. I've mentioned before that cartoons are often a big deal in the TF community, as many kids cartoons contain TFs and that was often our first exposure. Shrek was a big influence for me on an intellectual level and in terms of the aesthetics of the TF itself. Others have mentioned different cartoons and TFs, like the AP sequence in Snow White.
It's with this in mind that I'm taking a hard look at gender coding in Pixar's Lava, which is s short film that many of us saw aired before "Inside Out." The linked essay makes some good points about how we tend to "code" anything animated as male by default, and female if it contains feminine features, like a bow or long eyelashes. It also brings up the good point that we tend to perceive women's heterosexuality by how attractive they are to men, not how attracted they are to men - hence the stereotype of a frumpy, ugly lesbian who goes for women because she can't get a guy.
As a writer, I find this interesting, and I think the piece is mostly correct. Romance is usually one way in movies (it's all about the man's desire for the woman and how he can prove the sincerity of his love, not the other way around) and that makes things boring.
So what does this have to do with transformations? Well, as a writer I always strive to write in such a way that I'm not just telling the same story over and over again. When a female character gets transformed in a way that causes her to lose traditionally valued aspects of her physical appearance (this happens at some point in most of my stories,) I feel it's important to describe what she wants to do about it, not just how the world treats her differently. Many of my female characters become more active after their TF, seeking out romance with a more dominant role or seeking out new, previously closed off avenues of personal fulfillment. I think that makes things more interesting than just exploring how the world devalues her now that she's not "pretty" anymore.