The Former Life of Brian

When Brian is afraid that he has lost his chance at love, he goes in search of a former flame, Tracy, only to discover he is the father of her unruly son, Dylan. From Family Guy Season 6.

Also, Dylan is scheduled to show up in Family Guy Season 7 in “Son of a Brian”:

6ACX29 “Son of a Brian”: Brian’s son, Dylan, returns after Tracy dies of heart disease. So Dylan is now forced to live with Brian for the rest of his life. Worried about Brian’s obsoleteness from before, Lois tries to make sure it doesn’t happen again. Meanwhile, Peter gets a job at the drunken clam after being fired from the brewery, and goes on a long drinking spree.

Here’s the episode!