I would see 33/66 female male ratio in the police force as unusually high ratio of women for a police force. Claim that women are rare in your police force would be, simply, a lie. In addition, we are talking amount main characters in books here. It is easy to ignore books you are not interested in. Books wont "be tough" to other books.

Plus, bookstores have those "for boys" and "for girls" sections. Harry Potter and anything popular with main male character is in boys section. Both girls and boys are buying those from boy section. It is simply not true that finding a book with boy male character would be some kind of hard. They are right there. And unlike what others in the thread think, there is variety - there are funny books, action superheroes and more nuanced stuff.

Many parents do see reading as a girly activity tho. And will even explicitly refer to reading as something only girls do, openly in front of boys. But it is not the matter of male characters being rare.