Yeah, the "singular they" is very tricky- gender-neutral stuff is a very recent development, I feel. Personally I'd go with "they" or "it", but the rules haven't really been established yet.
Also: "In the late 20th century, the feminist movement expressed concern regarding the use of generic he in the English language. The feminist claim was that such usage contributes to an assumption that maleness is "standard," and that femaleness is "different". It also claimed that such use is misogynistic. One response to this was an increase in the use of generic she in academic journal articles from around this time."
hurr feminism