I was intrigued by this post on the Romantic Times message boards:
"I very occasionally read contemporaries and really dislike the careless use of four-letter words coming out of the heroine's mouth. To me that is not romantic!"
I imagine this depends on the age of the reader, among other factors. But I actually prefer heroines who aren't afraid to use swear words, even crass ones. Your characters don't all have to swear like sailors, but it seems to me that if you're going to write realistic young people (and I'm defining "young" here as under forty-five or so!) they need to cuss occasionally. Let's face it, most people do cuss nowadays. To me, having female characters that never swear is a lot like having all your books feature thirty-year-old virgins-- both are throwbacks to past ideals of female behavior, rather than an effort to realistically represent the current culture.