Warner Bros.Joey discovers Rachel is pregnant in "The One with the Red Sweater". He reveals that he has a red sweater in the apartment and believes it belongs to the father. Phoebe recalls Tag wearing it. However, Tag was wearing the exact same sweater when she tried to return it. Ross, of course, was the father. Tag, however, runs into Tag in the street and asks "So whose sweater is it?" Ross thinks he is talking about the sweater and says, "I don’t know, an Italian guy." You can read your label. It's awkward, but it's iconic.
