Individual human beings don't "evolve." Evolution happens over generations. Any discussion of any individual organism "evolving" is simply wrong.
Nice tap dance. You should audition for America's Got Talent.
However, there have been individuals with XY chromosomes that have a uterus and given birth.
That has nothing at all to do with my question. At no point whatsoever did I mention chromosomes, because sex is not defined by chromosomes.
Sex is
defined by the type of reproductive systems that a species has evolved. Sex is
determined (as in provides instructions and sets the pathway for a fetus to develop) by different mechanisms in different species. In mammals, that mechanism for determination is chromosomal karyotype, with XX resulting in a normal female and XY resulting in a normal male. Some karyotype variations can occur as a result of anomalies, interruptions, and mutations... but they don't alter the mechanism or the definition. No more so than the existence of people with Down Syndrome changes the definition of humans having 46 chromosomes in 23 pairs.
The mechanism is different in different species. For example, the mechanism for sex determination in alligators is the temperature of the nest at a key point in fetal development. When it's above a certain temperature, the fetuses develop as females; when it's below that temperature, they develop as males (or maybe the other way around, I don't recall). If some random yahoo comes along and blasts one side of an egg with a torch and the other with some dry ice, and the fetus gets all messed up... that doesn't change the definition of what male and female are in alligators.
Consider a very simplified analogy. Let's say that there are two types of buildings in the entire universe, houses and garages. There are some ways in which those are the same, and other very important ways in which they are different. In this universe, houses have plumbing and electric and closets; garages have rolling doors and concrete floors. Those are the
definitions for houses and garages. In order to produce a house or a garage, builders use blueprints, and those blueprints all show up through a gigantic blueprint fax machine. The blueprints are the mechanism for building
determination.
Sometimes the fax machine hiccups, and the blueprints get messed up. Sometimes the fax machine works just fine, but Jared spills coffee all over the blueprint and the layout gets screwed up. That results in errors during the building process. Every now and then, a blueprint for a garage errantly has an electrical outlet in it with no actual electrical lines attached... but it's still recognizably a garage even though it has an outlet attached to nothing. Sometimes a blueprint for a house slaps a rolling door on the back in addition to the electricity and plumbing and closets, but it's still recognizably a house. Sometimes the blueprint is labeled "house" but it has a rolling door and concrete floor and has no electricity, plumbing, or closets... so despite the blueprint saying "house" everyone who looks at is can tell it's a garage, and nobody puts their dresser and TV in there. And very, very, very rarely the blueprint is so messy that it's difficult at first glance to figure out if it's a house or a garage - but with a bit of work and some common sense, we'll come to an agreement about how to use the building.
Now... even with the 0.02% of times when the blueprint has an error... has that altered the definition of "house" or "garage" in any way whatsoever?