He is not a female by definition.
Female (♀) is the sex of an organism, or a part of an organism, which produces non-mobile ova (egg cells). Most female mammals, including human females, have two X chromosomes.
a person bearing two X chromosomes in the cell nuclei and normally having a vagina, a uterus and ovaries, and developing at puberty a relatively rounded body and enlarged breasts, and retaining a beardless face; a girl or woman.
an organism of the sex or sexual phase that normally produces egg cells.
of or denoting the sex that can bear offspring or produce eggs, distinguished biologically by the production of gametes (ova) that can be fertilized by male gametes
There are many sources. A man with a removed penis and some injections is not a female.
It also comes down to a Human Rights thing. Fallon has made the necessary strides to be considered a woman, in spite of emotional, psychological and physical trauma/turmoil/heartache. And has earnt the right to be called a woman.
But MC, I know you're a nice guy, this is a touchy area fo sho!
I've known close to 15 T-Girls over the years, and I always show the common courtesey of calling them female...I feel they earnt that right...it ain't an easy road
If a person wishes to be called a female then that is fine, people have the right to ask to be called whatever they want, as you said I'm a nice guy I'm not here trying to be rude to Cowgirl or whoever, I'm just pointing out what is there.