The One with the Donor

S9 E22: Disappointed to learn that they cannot conceive a baby naturally, Monica and Chandler mull their options. When Chandler brings home a handsome, unknowing co-worker, Zack (John Stamos - "Full House," "Thieves"), for dinner, Monica and Chandler embarrassingly "interview" him as a potential sperm donor. Meanwhile, while shopping with Phoebe, Rachel confides that she is enamored with Joey. Unfortunately, Joey's current girlfriend, Charlie (recurring guest star Aisha Tyler), overhears. And Phoebe encounters a boyfriend, David (recurring guest star Hank Azaria), from long ago.