This is an interesting article from Inside Higher Ed, about a new study examining the different words used in letters of recommendation to describe male and female applicants for faculty positions (and the impact of those descriptions): 

http://www.insidehighered.com/news/2010/11/10/letters

Here’s a link to the journal article discussed:

Madera, J.M., M.R. Hebl, and R.C. Martin. 2009. Gender and Letters of Recommendation for Academia: Agentic and Communal Differences. Journal of Applied Psychology 94(6): 1591-1599.