"Cartman's Mom Is a Dirty Slut" is the 13th and final episode of Season One, and the 13th overall episode of South Park. This is the first of a two part episode; the second part being "Cartman's Mom is Still a Dirty Slut". It originally aired on February 25, 1998.
Eric Cartman is in search of his father but no one is owning up to the job. Could it be Chef? Or is it Mr. Garrison? Or the 1989 Denver Broncos? It could be anyone who attended South Park's 12th Annual Drunken Barn Dance. Cartman just has to know, and only an expensive genetic test stands between him and the true identity of his father. Stan, Kyle, and America's Stupidest Home Videos may be the answer to Cartman's prayers.
In a classic cliffhanger, Cartman needs to find out who his father is but his mom is no help. Learning that his father could be one of the many people that his mom "had relations" with during an annual party called "The Drunken Barn Dance", he finds that there's more to his mother then he thought.
Based on everyone's best recollections of the time, candidates for the identity of Cartman's father are limited to Officer Barbrady, Chef, Jimbo, Ned, Mr. Garrison, Chief Running Water, Gerald Broflovski, Dr. Mephesto, Kevin, and the 1989 Denver Broncos. Dr. Mephesto is willing to perform DNA testing to resolve the issue, but requires $3,000 for the test. In the meantime, Kyle, Kenny, and Stan videotape Cartman having a tea party in his backyard with stuffed animals. They come up with the idea to send the video into America's Stupidest Home Videos for the chance to win $10,000. Cartman then approaches Kyle and Stan (Kenny was since killed by a train) with the depressing news about his lack of funds to find out his real father. Stan and Kyle agree that if they win the video contest they will give Cartman the $3,000 needed for the DNA testing. Cartman is overjoyed, but quickly becomes extremely angry after seeing the aired video. Cartman loses but comes in second with the $3,000 dollar prize enough for the DNA test. The narrator concludes the episode with a cliffhanging question, "Who is Eric Cartman's father?"