transboy!dipper headcanon is true/valid for these reasons:

  1. they have compared mabel and dipper to stanley and stanford
  2. stanley and stanford are the same gender and sex, so they’re identical twins, meaning they were split from the same embryo 
  3. there may be no quotes from alex hirsch yet saying mabel and dipper are fraternal or identical twins yet but it is likely they are the same type of twins as the stans
  4. there was a whole episode about dipper proving his manliness
  5. dipper still gets upset when people call him weak by calling him a girl

Dipper is a transgender lil dude