That more than one in five of young women's dreams these days are about sex is a new development: A similar dream study in 1966 found less than 4% of young women's dreams were about sex. According to the researchers behind the latest study, the increased frequency of sex dreams among women “could reflect the evolution induced in modern societies by the feminist movement.”
“One might speculate that younger women in modern society (post-feminism era) deal with sexuality as a topic more openly than older women of previous generations,” they write in the paper on their findings.
Women have a lot less internalized shame around their sexuality, and therefore they might feel more comfortable talking, thinking, and fantasizing about sex—and therefore dreaming about it. As the researchers explain, “Dreams reflect waking life experiences.” The more time you spend thinking about something (or doing something), the more likely it is to appear in your dreams.
Additionally, it's possible that women are more comfortable admitting that they're having sex dreams in the first place and thus are more likely to recall and report them to interviewers.