The canon theory is more that they originally had ridges but augmented themselves to look like humans for the sake of espionage. Over time that became seen as cowardice so they reverted back. The real reason, of course, is make up budget.
I highly doubt the transgender alien child forced to convert for the sake of conformity to their culture was just a bit played for laughs.
Not any different than the way I have them, except I don’t have remoulade and prefer dill relish instead of whole pickle slices on hot dogs
But sir, it is only wafer thin
It’s important to recognize that women are equally capable of waving around a kitchen knife.