it is the hornone itself that exists in a spectrum. this is the part so few people grasp.
have you ever wondered why some women are curvy bombshells and others look like boys their whole lives? some get more estrogen than others. it's complicated - genetics, environment, experience, diet - but there's not a gene for huge breasts or a gene for manly calves. it's just hormones. it's just chemistry.
all of these questions - not homosexuality, mind you, but gender - revolve around these hormones, what proportion of them we have and what proportion of them we want.
my first shrink tried to get me to answer why i didn't want to just take steroids, if i was unhappy with my body image - and i had no meaningful answer for him, other than that i didn't want to. there isn't one....