Middle-Earth has a history of being very male-dominated. The Hobbit had no female characters whatsoever and the main plot of The Lord of the Rings centered around the (all-male) Fellowship. Across all the writing he did on Middle-Earth's history, the majority of his great heroes are men. Female Hobbits never got much focus and Dwarf women are famously referenced only in a single line of dialogue. To his credit, many of the women Tolkien wrote were strong characters. It was, after all, Eowyn who finally defeated the Witch-King of Angmar. But these tend to be the exception rather than the rule. Funnily enough, one of those exceptions ended up being one of his most interesting characters.