Lets add into the discussion then that if a woman wants to dress up in a schoolgirl outfit is this because of a particular reason that they find the whole Schoolgirl /Teacher type thing to be a turn on?
Now that's a difficult question to answer. Most people have fantasies and people don't always have the answer to the reasons why or where such a desire even comes from. This goes for both men and women. Sometimes it's just because it feels good. Other times it may be because it was something they read in a book or saw in a TV show or movie.
There are very good reasons why there are very advanced courses taught on the subject of human sexuality in universities around the world. The human psyche is a very complex thing.
To address your specific example of a woman finding that dressing up in a schoolgirl outfit turns her on, it could be any number of things. Maybe she saw a movie with a scene in it and she thought it would be fun to try. Maybe her best friend called her last week and said, "OMG! You have just GOT to try this!!!". It could also go back to something in her past when she was younger. I don't think any of us have the requisite psychiatric degrees to delve into that, though.
At the end of the day, all you can hope for is to find a partner who either enjoys the same fantasies as you do or at least accommodates them for you because they love you & you provide the same for them.
This is a very interesting topic you have brought up, Haggis, but I don't know how far we are going to be able to go because I don't think there are any definitive answers. There are probably just as many different reasons a person enjoys a particular kink or fetish as there are kinks and fetishes to be enjoyed. Even if some brave lady were to pop in her and express her views on why dressing up in a schoolgirl outfit really does it for her, that'd be just one viewpoint. The lady next to her who enjoys the exact same things may have an entirely different reasoning.
And just to drive spenser.d's point home, fantasies are different than pedophilia.
(Let's get this thread really fired up now....read on!)
Oh! Hey! Maybe we should discuss this from the other side of the fence? Maybe we should discuss young 14-17 year old girls who do their darnedest to dress and act like they are in their 20s and actively pursue older men (say, 28-40 year old males)? Should men start doing a background check on every potential date from now on for fear of falling into a trap like this? If a man falls into such a situation and is branded a pedophile, what punishment should the girl receive if she was actively pursuing and deceiving the man?