Before contemporary gender theory challenged the distinction between male and man, there was also a common distinction, e.g. by "becoming a man". A man is a male human adult, and the idea of adulthood is to some degree fluid. The legal age limit of 18 or 21 suggests that this is/was when we consider humans adults. But notions of "when your brain fully develops" suggests ages of 25-28 for men. Other factors involve when your beard grows big enough, and when children on the sidewalk saying "that man" about you. Society seems to have a duck-typing approach to what a man is, i.e. when a male human transitions from boy to man. And indeed, transgender men fit the duck-typing of society to a point where "strongly influenced by testosterone" seems like just as good a definition of, at least, "manly". Contemporary Western culture would have that you can make all sorts of other transitions at different points.