As the prefix hetero- followed homo- in the 1950’s, so has trans- with cis- at the turn of this century. Cisgender or cissexual was first coined on the internet in the mid-1990’s, and later picked up academically (in particular queer studies) to refer to individuals who are not transsexual and who have only ever experienced their gender identity and physical sex as being aligned. It is actually quite practical and has its roots in chemistry where cis- and trans- are used to describe molecular isomers, or ‘reflections in a mirror’, the same but not at all. Similarly it is now applied to the binary individual: transman vs cisman and transwoman vs ciswoman. As to whether a transperson becomes a cisperson following transition… let the debate begin!