Like women more generally, many trans women are feminists. Feminism and transgender activism are not in any way incompatible or mutually exclusive. A… - Julia Serano

People tend to harbor essentialist beliefs about sex — that is, they presume that each sex category has an underlying "essence" that makes them what they are. This is what leads people to assume that trans women remain "biologically male" despite the fact that many of our sex characteristics are now female. However, there is no “essence” underlying sex; it is simply a collection of sexually dimorphic traits. Some people will presume that sex chromosomes must be this "essence," even though we cannot readily see them, plus there are non-XX or XY variants. Others presume that genitals are this "essence" (probably because they are used to determine our birth-assigned and legal sex), although they can vary too, and may eventually change (e.g., if one undergoes sex reassignment surgery). In day-to-day life, we primarily rely on secondary sex characteristics to determine (or more precisely, presume) what sex a person is — and of course, these traits may change via a simple hormone prescription. Like I said, there is no mystical “essence” underlying sex.

Trans women do not transition out of a desire to be feminine; we transition out of a self-understanding that we are or should be female (commonly referred to as gender identity).

Many cissexual people seem to have a hard time accepting the idea that they too have a subconscious sex — a deep-rooted understanding of what sex their bodies should be. I suppose that when a person feels right in the sex they were born into, they are never forced to locate or question their subconscious sex, to differentiate it from their physical sex. In other words, their subconscious sex exists, but it is hidden from their view. They have a blind spot. (5 - Blind Spots: On Subconscious Sex and Gender Entitlement)