Get married
Johnny (age 8) comes into the house for dinner after playing outside all afternoon. His parents ask him what he did today. He says that he played baseball and then he proposed to Betty (age 7) the next door neighbor. They are going to get married. His parents think this is cute, and they don't want to make fun of Johnny so they ask Johnny him "How are you and Betty going to pay for the expenses of being married?" He replies "Well with the $1 I get each week from you and the $1 she gets from her Mom and Dad, we should do o.k." His father says "That's fine, but how will you pay the extra expenses if you and Betty have a baby?" Johnny answers "Well, so far, we've been lucky..."