Trans women who are conventionally feminine are not in any way asserting or insinuating that all women should be conventionally feminine, or that fem… - Julia Serano

Women who insist that trans women are not women often object to being called “cis women” under the false assumption that it somehow undermines their femaleness — this is not at all the purpose of this language. The sole purpose of cis terminology is to name the unmarked majority (similar to how one might refer to white women, or heterosexual women, or able-bodied women, etc.). In other words, referring to someone as “cisgender” simply means that they have not had a transgender experience.

The most infuriating assertion regularly made by the "trans women are biologically male" camp is that trans people are somehow "denying" or "erasing" biological sex differences, and that this hurts cisgender women/"[w:Female|biological females]].” This is patently untrue. I can assure you that trans people are highly aware of biological sex differences — the fact that many of us physically transition demonstrates that we acknowledge that sexually dimorphic traits exist and may be important to some people! I would reframe things this way: Transgender people often have a more complicated relationship with our sex-related traits (as they may be discordant with our identified and lived genders), and thus the language that we use to describe or discuss these traits may seem arcane, or nonsensical, or unnecessary to the average cisgender person. And because they are unfamiliar with this language (and/or flat-out antagonistic toward us), some cisgender people will subsequently misinterpret this language and differing perspective as some sort of "denial."

While gender socialization is quite real, all of us are capable of overcoming or transcending the socialization that we experienced as children. And gender socialization doesn’t simply stop when one reaches adulthood: All of us are constantly facing gender-related social pressures, expectations, and obstacles throughout our lives. If you believe that these statements are true for cis women, then they also must be true for trans women.