Or, maybe the book is just about how you treat a "guest." Or, perhaps it's Biblical. If the mouse asks for the boys' shirt, then the boy should give his cloak as well. Or, the mouse and the boy are both male to demonstrate that males can carry out the nurturing role that is usually confined to women. Or, maybe the book features a male protagonist because the author didn't want to portray a female protagonist who might shriek at the sight of the mouse, thus denying the precipitating action for the story. Or, the book is promoting inter-species love. Or, maybe some grown-ups should just leave such books to me so I can read them to single-digit kids and just let them enjoy them.