Science regarding transexualism


Medical transition & biological sex
There are many ways to arbitrarily divide humans into 2 sexes but what actually make sense is to look at the body itself.

Reproductive sex
Humans can produce sperm nand eggs to reproduce. As far as i know there is no case of a human being able to produce both or transition from producing one type of gamete into producing the other.

This is relevant when it comes to partner selection since both sperm and egg are required for successful fertilization.
Unfortunately HRT will over time prevent your body from producing sperm without you getting the ability to produce eggs in return, this does change your reproductive sex from male to infertile unless you find away around in such as by banking sperm.

One of the advantages with cis + trans female relationships is the ability for them to have biological children together, two cis lesbians currently do not have that option.

HRT will give you fully functional female breasts

HRT alone can give you a body that looks like that of a female except for genitals (you would still need surgery for that) if it's started early enough and you have genetics for it, in other cases a female appearance is obtained after surgery.
With a female appearance you will function in society socially mostly like a female, early social transition result in early female socialization which will make it easier to fit in with cis females.

The brain
Trans females have brains somewhere between the male and female (average) prior to HRT and after male puberty.
Trans females in general (prior to HRT)
Trans female attracted to females (prior to HRT)

The study (picture and link above) is a bit strange since they have an abstract that doesn't fit with their actual results. The sample size is also smaller than ideal making the results a bit unreliable.

HRT will of course have a powerful feminizing effect on the brain changing it towards female proportions unfortunatily that study used "Cyproterone Acarate" at 10 times the appropiate dosage which may have skewed the results.

HRT will affect your penis so it will no longer be the same as a male penis

I will try to find some good studies regarding this but based on what trans females have written about this it does seem like a change in sexual function (multiple full body orgasms, less visually focused, etc) is to be expected from HRT. Some people have also resorted a change of sexuality resulting in them becoming more interested in sex with men.

Cis females like trans females often enjoy things like revealing clothing, this is not to attract male attention, it's for themselves.

This can unfortunately get out of control in individuals who are not yet on HRT due to the resulting powerful sex-drive. You will still likely enjoy having a beautiful female body on HRT but it will be more like comfort and less of a sexual thing.