http://en.wikipedia.org/wiki/Mandarin_Chinese_profanityexcerpt:
Insults
As in English, a vulgar word for the sexual act is used in insults and expletives:
* cào (肏/操) = fuck (the variant character 肏 was in use as early as the Ming dynasty in the novel Jin Ping Mei). 操 is usually used as a substitute for 肏 in print or on the computer, because 肏 is often not available for typesetting or input.
* cào nǐ zǔzōng shíbā dài (肏你祖宗十八代) = fuck your ancestors to the eighteenth generation
* cào nǐ zǔzōng shíqi dài (肏你祖宗十七代) = fuck your ancestors to the seventeenth generation
* cào nǐ zǔzōng shíliù dài (肏你祖宗十六代) = fuck your ancestors to the sixteenth generation
* cào nǐ zǔzōng shíwu dài (肏你祖宗十五代) = fuck your ancestors to the fifteenth generation
* cào nǐ zǔzōng shísì dài (肏你祖宗十四代) = fuck your ancestors to the fourteenth generation
* cào nǐ zǔzōng shísan dài (肏你祖宗十三代) = fuck your ancestors to the thirteenth generation
* wǒ kào (我靠) = fuck! or fuckin' awesome! or holy shit! (Originally from Taiwan, this expression has spread to the mainland, where it is generally not considered to be vulgar.)
this article was clearly written from taiwanese slang. I believe the mainlanders use a slightly different set. I like how the guy enumerates all the diffrerent nnumbers of generations...bahaha
though I beleive the correct term is actually
肏你十八代祖宗