“Once gendered behavior has been determined, however that occurs, cisgender males don’t say “I’m a boy!” for cognitive reasons that are substantially different from the reasons that transgender males say “I’m a boy!”
Except “cisgender” boys don’t generally engage in questioning “am I really a boy”.
The obvious answer is “No”. In fact this experience seems suspiciously like trying to make oneself belief that one believes one’s gender to be X.
While we’re assigning categories in complete defiance to common sense and evidence, why are we so sure that the category “human” is applicable?