There’s unbelievably large quantities of evidence, both historically and cross-culturally, that one’s biological sex does not determine one’s gendered social status. That is, that being “a human male” doesn’t automatically make one “a man.” The gendered social status of “man” is an ongoing ritual accomplishment, not the inevitable unfolding of biology or anatomy. We don’t even need to look at the evidence for gender variant or transgender people to see this is true.
If this is a subject that interests you, David Gilmore’s global overview of manhood is eye-opening: David Gilmore, Manhood in the Making: Cultural Concepts of Masculinity (New Haven: Yale University Press, 1990). Serena Nanda’s short overview of gender variant people globally is also helpful here: Serena Nanda, Gender Diversity: Crosscultural Variations (Waveland Press, 2014). But these are just summaries of truly huge amounts of research and evidence in sociology and anthropology showing that biological sex doesn’t determine gendered social status. Surely you can’t suggest all this evidence is the product of “mental illness”?
But if you persist against all evidence in believing that “male human = man” let me be the first to expose you to this typical phase in the life course of all males: being a boy.