A father of a young girl comes and meets the doctor.
Father: Doctor, how is my daughter's report?
Doctor: Congrats, your daughter is pregnant.
Father: WTF ?????? My daughter is 10 years old and unmarried.
Alright listen up, nimrod. The joke is that the doctor tells the father that his 10-year-old daughter is pregnant. The absurdity comes from the fact that a 10-year-old being pregnant is generally unexpected and, you know, biologically weird. I would expect a guy like you to not understand this kind of joke.