I can't really say that I've noticed the absence of female characters particularly, either from what I've read or my children.
Joan Aiken is the first one to spring to mind-look at Dido Twite, definitely strong female character there.
Elizabeth Goudge generally had the female characters as the lead, Noel Streatfield, Monica Edwards, Gwendoline Courtney....
But I don't think male authors exclusively write about male characters.
Arthur Ransome: Swallows and Amazons has 4 girls to 2 boys and Nancy is really the leader and strongest character, and, if you had to pick a main child, Titty would get that accolade.
In the Coots series, it is mostly boys, but, as the only girl who features throughout the books, Dorothea is really in charge, especially in "The Big Six", they all look to her for a lead and ideas.
Malcolm Saville's Lone Pine series the girls take as big a part usually as the boys, and Mary is definitely the leader of the twins. In his other series (Buckinghams/Jillies etc) the girls are often the leaders, and the only books I can think that he only wrote with one main character they were female (eg. Jane's country year)
Yes, there are books that are male biased. Alex Rider for example, but are you really thinking that shouldn't be allowed.
When I write, my main character tends to be female simply because I am more comfortable with writing that way. At the moment the one I'm writing has a disability too. She has a disability I'm very familiar with, as it's what dd has. I would not be comfortable with writing about a disability I knew less about because I know how frustrating it can be reading. In the same way, I'd rather someone wrote what they are comfortable with.
I didn't invent a story or characters they invented themselves and shouted at me until I listened to them. That is a very good way of putting it.