It's upsetting that your brother isn't accepting. I'm sure it would be nice to have a sibling that accepted you

I'm only child sooo I can't really relate, but hopefully your brother comes around soon.
My boyfriend and I have been together for over a year and he prefers trans women. He knew I was trans before we dated. I would have to agree with Roseana that if someone loves all of you, you shouldn't hate them. My bf doesn't solely go for trans girls, but heavily prefers them. Like if I had an exact twin, he'd go for the trans version

I don't think he is a ->-bleeped-<- anymore than I am a cis-women ->-bleeped-<- because I prefer a vagina on a woman. Just preference

Then I think there is the alternative that, like Angelique said, doesn't care if your extremely masculine looking and identify as a trans-women and they pursue rather aggressively with a fixation on the genitals.