EXCELLENT article on the film
This article, although long, explains a lot of the under-currents in the film, and provides some interesting insights into the nature of Tenoch's and Julio's relationship. It also tackles the (ridiculous) censorship of the US video market. Keep in mind it was written in 2009:
http://ejumpcut.org/archive/jc51.2009/tuMamaTambien/index.html