"The word has its origin in the Latin-derived prefix cis, meaning "on the same side" as in the cis-trans distinction in chemistry. In this case, "cis" (on the same side) refers to the unity of a gender identity with a biological gender assignment.
[edit]Internet use
The word cisgender has been used on the internet since at least 1994, when it appeared in the alt.transgendered usenet group in a post by Dana Leland Defosse.[2] Defosse does not define the term and seems to assume that readers are already familiar with it. Coinage has been attributed to Carl Buijs, a transsexual man from the Netherlands, in a number of internet publications.[3][4] which suggest that he proposed the term in 1995. It may have been independently coined -- in April of 1996, Buijs said in a usenet posting "As for the origin; I just made it up".[5]"
http://en.wikipedia.org/wiki/Cisgender
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Academic use
The term has more recently been used in scholarly publications, such as a 2006 article in the Journal of Lesbian Studies[6] and Julia Serano's 2007 publication Whipping Girl.[7] Serano also uses the related terms cissexual,
which she defines as "people who are not transsexual and who have only ever experienced their subconscious and physical sexes as being aligned."
I do believe I need another beverage...