Are sci-fi and fantasy fans more likely to be feminist? I really don't know, but I've been wondering about it lately, and I'm thinking the answer miiight be yes, based solely on anecdotal experience and the themes that showed up in the books I read as a kid. If anyone knows of any actual, real, hard core data on this, I'd love to know! But... it's a topic worth thinking about, overlap and interplay between sff and feminism, because some books.movies/games in the sff genres are extremely supporting of feminism, but others really... are not, and lack female characters or at least female characters that are developed in the same way as men and have roles beyond sex object and mother. Plus, fan culture revolving around certain extremely popular sff franchises can be actively hostile towards women-- so those fans certainly aren't getting any sort of feminism boost.
But my big thought right here is that girls who grow up reading sci fi and fantasy? i think they're more likely to turn into feminist women than girls who don't. And this is in large part because, even though it is very easy to find books with extremely harsh male characters and no real female characters of substance, it's also quite easy to find books that are gender neutral or that are directed at girls. I got to thinking about this for a couple of reasons-- 1. I just read Octavia Butler's oeuvre-- she was a black feminist woman writing sci fi in the 70s and under her own name, 2. I found out about James Tiptree Jr., a popular Scfi author who wrote under an assumed name but who has since been honored with an award for female scifi authors in her name, and 3. a lot of chatter on feminist blogs in the past year or so discussing The Ten Thousand Kingdoms, the third book of which I am STILL trying to get around to reading.
In thinking about some of the formative sci fi and fantasy books of my youth, there are a lot that have female warriors or female characters with power-- The His Dark Materials trilogy, Patricia C. Wrede's The Enchanted Forest Chronicles, Tamora Pierce's Song of the Lioness Quartet, Anne McCaffrey's Pern and Rowan books, and things by William Sleator. While romance is often a factor in these books, it isn't usually the main focus-- instead, general character development and struggles on a kingdom or world level tend to take place. Granted, a lot of modern fantasy and sci fi aimed at young adults are just romance novels in different wrapping (and I have to admit, The Vampire Diaries started when people my age were young, and I read them when I was a tween too), but I think that people my age who grew up reading some of these books sort of developed the idea that women are individuals in the same way that men are individuals, rather than just a simple stereotype.
But like I mentioned above, it's really easy to avoid the feministy stuff, especially if a reader doesn't want to follow a female protagonist (and traditionally, surveys have shown that girls are more likely to read stories about boys than boys are to read stories about girls), and a lot of men who grew up on the more male dominated sides of sci fi and fantasy have turned out to expect women to fall into only a few categories and get bitter when women don't follow a certain script of acquiescence. So I honestly have no clue how things fall out, but I'd love to hear other folks' takes on this.