A Daughter and Her Father's Opinion on Abortion

So, a daughter asks her father, "Dad, what is your opinion on abortions?" Her father says, "Why don't you ask your sister?" The daughter responds, "But I don't have a sister... Oh."

Explanation

Experiment

The joke plays on the implication that if the father had a different opinion on abortions, the daughter might have had a sister. The punchline comes from the daughter realizing the implied meaning, highlighting a kind of dark humor.