There are two possible groupings of man and woman, the gender based version and the sex based one. Most posters on this forum believe that the sex based grouping is the correct one and that the gender based grouping makes no sense and has no credible criteria by which the people in the group woman are placed there.
In order for the grouping to make sense, there has to be something that a woman has in common with a transwoman that she does not have in common with a transman. No-one has ever been able to define this, other than with respect to the sex based grouping.
It can't be based on identity, because the women on this board think of themselves as a member of the sex based grouping woman, not the gender based grouping woman.
It takes huge amounts of mental aerobics to defend the gender based definition and none at all to support the sex based definition.
In fact, the only definition that makes sense of the gender based grouping is, "Do you feel that you belong in the sex based grouping of women?"
But even this doesn't work. If you make admission to the gender based woman determined by whether or not you WANT to be in the sex based grouping women, then you exclude a huge amount of actual women, who have no particular desire to be one.
If you make admission to the gender based woman, do you believe you are in the sex based group woman, then you excude many transwomen, as we are constantly told they understand the difference between sex and gender.
So the only answer that holds up is that entry into the gender based definition of woman is different depending on which sex you are. Men are allowed to have the gender woman simply by wanting to have the sex of a woman. Women, on the other hand, are there by default just by being in the sex group woman. It can't depend on whether they want to be there or not, because those damned gender criticals won't agree to that.
So, the gender based definition of woman, from a transwoman's perspective is, "I'm in this group because I want to be, and you HAVE to be in this group because I only want to be here if you are too."
Calling yourself cis is capitulating to this nonsense, self-serving thinking.
The sex based definition is the only one that is needed, the only one that makes any kind of sense at all.