I don't read or write fanfic, so this doesn't affect me directly, but I can recognise dodgy science when I see it. You do not announce a research project in the following manner.
We're deeply interested in broad-based behavioral data that involves romantic or erotic cognition and evinces a clear distinction between men and women. Fan fiction matches this criteria perfectly. Let us make clear, however: fan fiction is not the subject of our research. Our subject is the human brain. For us, fan fiction is a wonderfully rich source of data--like single-neuron recordings in rhesus monkeys--albeit a unique and invaluable one.
Firstly, from the wording it seems that they are not interested in any data that might contradict their basic assumption. Heaven forbid that their pre-conceived ideas might be challenged! Secondly, likening a phenomenon as complex and socially constructed as fan fiction to a neurological process that occurs when a monkey sees an object makes me go WTF?!
A full summary of the opposition to the survey can be found here and the survey originator's LJ is here. The survey is currently down while they "digest all this great feedback". However, if/when the survey reappears, I suggest that you don't take it and that you advise people you know in the fannish community not to take it either.
Basically, this is not proper science. What they're proposing is a travesty of the scientific process intended to produce "evidence" for a popular book in which it appears the "researchers" will expound their ready-formed biases and opinions.