Simon/River is the pairing between the siblings Simon and River Tam. It is often called CSI for Crazy Space Incest.
Many fans see Simon and River as being the most important person in each others' lives, with their pairing winning over even some fans who would normally describe incest as "squicky
The tension seemed pretty clear long before the dvd revealed the cut scene from "Our Mrs. Reynolds" where River stuffs a pillow under her shirt and announces to all and sundry that she’s having Simon's baby. 
The CSI Shipper's LiveJournal Community, light_it, was created in October of 2004. It went to moderated membership, with all posts automatically set to be viewable by community members only, after the events of Strikethrough in 2007. It remains active, with over 250 members as of June 2009.
At one point there was a Simon/River archive known as the CSI Fanfiction Archive, run by paperdollgirl, but it no longer exists.
- ↑ T.W. Lewis/gardendoor, Crazy Space Incest: Simon/River (Firefly). Accessed June 09, 2009.