Why are there so few female characters inTolkien's work?

I have read the books and I was surprised by the fact that there few women in his stories. Arwen and Galadriel are important characters but they don't appear as often as male characters do. In Hobbit there are almost no women. I was thinking of that when I read that Evangeline Lilly will join Hobbit as a female elf. Has ever Tolkien commented on the luck of female presence in his books? C.S. Lewis, Tolkien's contemporary and friend, included strong female characters in his stories. I would like to know why Tolkien was less eager to do so. Women in his books are distant creatures of beauty and wisdom that hardly participate in the events that surround them.