Surely younger women are less likely to have be steered as firmly by our society into heteronormative sexuality patterns. Indeed, other statistics show that younger women are much more likely to experiment with bisexuality and lesbianism.
For the first time in human history women are able to think seriously about lesbian sex and love. For the first time in history women can read about it and see it. And decide that they prefer looking at it and reading about it, rather than about straight sex.