Gender Dysphoria

One thing I have a hard time getting my mind around is transgender individuals, often referred to as those experiencing gender dysphoria.  I, personally, grew up gay.  As I look at my young childhood through that lens, I can see aspects that may have indicated my orientation.  Or it may just be confirmation bias.  Regardless, I never doubted that I was male, and never even once wanted to be female.

I have been taught all my life that gender stereotypes were largely cultural.  Dresses, high heels, and makeup were not first developed for women's use exclusively, but eventually became culturally identified with females.  I have read that biological males who are transgender feel a strong need to wear female trappings.  They have a desire to express the cultural markers of females.  To me this is strange, because those cultural markers have little to do with actually being female, only our current perception of feminine appearance.

And another thing I don't know is whether or not transgender individuals' orientations follow their biological gender, or their perceived gender.  Are there examples of both?  Is one predominant?  Is it largely cultural, like their desire to appear culturally as their perceived gender, or is it biological, more like my own experience?  I don't want to sound rude.  I'm truly curious.