I don't think Tolkien purposely made it so there weren't many females, I think it's for many reasons including, but not limited to; in his time, men and women being equal wasn't a mainstream issue. The characters he imagined were boys, he didn't decide that, they just were. He wouldn't have changed the gender of characters for equality's sake. Also most men are more comfortable writing about males and vice verse. Please get your tits out of a knot and accept that nothing should be that equal.