People who fall for gender ideology conflate sex, primary sex characteristics and secondary sex characteristics.
Sex is chromasomal(Y chromasome present=male, absent =female ). If all goes to plan you are one of 2 karyotypes(Xx or XY).There are about 15 other karyotypes (X, XXY etc)but all are either male or female depending on the Y.
Primary sex characteristics are genitals and gonads, things set in action before birth, there is no overlap between the primary sex characteristics of the sexes, unless a person has one of a few well understood disorders of sexual development or intersex conditions. There are male dsds and female dsds. This does lead to a tiny cohort of males developing female genetalia, and occasionally even some internal structure (womb), but never the ability to produce the gametes (eggs/sperm) of the opposite sex. These people really can claim to have been assigned a sex at birth
There is no known overlap between dsds and being transgender.
You are either on the male reproductive path or the female. We are a sexually dimorphic species. We are dimorphic BECAUSE of our separate reproductive roles. Were we more similar, we would still be 2 desperate sexes.
Secondary sex characteristics are post birth changes and usually post puberty that are hormonally mediated such as fat distribution, breasts, voice depth, brow bone prominence, pelvic size, facial features, muscle percentage and type.
Many secondary sex chacteristics overlap, some massively, some barely at all so for any given secondary sex characteristic a male may be more 'feminine' than a given female and vis versa. Oestrogen and testosterone do affect the brain somewhat so the male and female behavioural profiles are overlapping but different on average. Out of this, the concept of gender was born. This is how a good woman should look, act, behave. Feminists tried to separate the concept to prevent biologically determined roles being forced on them. Women can behave in a masculine ways etc. It has been taken, twisted and is now being used to deny biology. Men still reject 'feminine' males.