Trans women are women

The Basics

A trans woman is a woman who was assumed at birth to be male, based on superficial physical characteristics. "Trans" is short for "transgender", a term which means "having a gender identity different from that which was assumed at birth". (Its opposite, which applies to the overwhelming majority of humanity, is cisgender or "cis" for short. A "cis woman" is therefore an adult human who was (correctly) assumed to be female at birth.)

• Objection: Women have uteruses and ovaries.
  • Reality: This is usually true, but there are many exceptions.

While such assumptions are correct the overwhelming majority of the time, they are occasionally incorrect to some degree. When such assumptions (and subsequent social role assignments) turn out to be incorrect, the result is a transgender person -- someone who has been perceived and raised as a gender which differs from the one with which they identify.

The word "identify" in that sentence unfortunately opens the door for a lot of misunderstanding about how gender works and why identity is the most important element, superceding any easily-measurable objective qualities.

• Objection: If we allow people to decide their own gender, it will cause serious social problems.
  • Reality: There's actually no evidence for this.

For any but the most narrow reproductive definitions of "woman", there is no reason to think that "trans women" are not a subgroup of the broader category "women". That's why the phrase is "trans women" and not "trans [something else]".

writing in progress