Bewitched S01 E12 And Something Makes Three

"Witches are people too!"

Larry sees Louise and Samantha entering an obstetrician's office and assumes Darrin is about to become a father. It is actually Louise who is pregnant, but she is afraid to tell Larry. After Larry tells Darrin, he has a daydream about Samantha having "witch" children. When the four of them have dinner that night, the truth comes out.