Sentence:  The <WSD>birls</WSD> forum describes itself as "a community dedicated to boyish/androgynous girls" with open borders such that "all people who don't define themselves as <WSD>birls</WSD> are welcome as well, including femmes, bioboys, androgynes, and transguys ... or you could just make up your own label for who you are" (Birls Live Journal, 2004). 
Meaning of the word marked with <WSD> tags:  A girl of boyish appearance.