Rock-a-Bye Munster

S1 E4: Grandpa and Herman mistakenly get the idea Lily is pregnant after overhearing part of a private conversation between her and Marilyn. Marilyn works as a baby-sitter for another family and they have asked Lily if the little boy she minds can stay with the Munster family while his parents are away on vacation. Although Herman drops a number of obvious hints, Lily refuses to say anything about the new arrival.