GURPS Sex
GURPS Sex refers to optional rules in the GURPS system intended to cover sexual events. There are two notable works including this as its title, distinguished by their subsequent title differences:
Books
1996
http://www.hoboes.com/pub/Role-Playing/Generic/GURPS/GURPS%20Rules%20for%20Sex/
2008
http://forums.sjgames.com/showthread.php?t=48925
Sex by Tim and Christine
On the web: https://www.eskimo.com/~vecna/gurps_sex.html
included character-building software: http://web.archive.org/web/20030619112915/http://thefountains.homeip.net:8080/games/Gurps/GCB/sex.htm