This reminds me of a story called "Family Doctor". A middle-aged couple and their teenage daughter all go to the same doctor.

First the man has his appointment:

MAN: "Doc, I need some condoms."
DOCTOR: "Why? You are married and I gave you a vasectomy last year."
MAN: "Errr... I am fucking whores on the side."
DOCTOR: "Hmmmkay... here's a box of a dozen."
MAN: "Thanks, Doc!"

Then the wife has her appointment:

WIFE: "Doctor, will you fit me for a diaphragm?"
DOCTOR: [Scratches head] "... sure."

Then the daughter has hers:

DAUGHTER: "Put me on the pill, Doc."
DOCTOR: "I can't... you're only 15, I need your parents permission."
DAUGHTER: "Hmmmkay"

A month later the Doctor has made an appointment with all three at the same time, unbeknownst to them. Surprised to see each other there, the Doctor sits them down and says:

"I have test results back and some news for each of you."

To the man he says: "I have good news and bad news. Which do you want first?"

MAN: "The good news."
DOCTOR: "Your daughter is not pregnant."
MAN: "So, what's the bad?"
DOCTOR: "I've been fucking her in the ass for a month."

Then he turns to the wife: "Same goes for you, I have good news and bad."

WIFE: "I'll take the bad first."
DOCTOR: "You have genital warts."
WIFE: "And the good?"
DOCTOR: "You are also not pregnant."

Finally, he turns to the daughter: "Well?"

DAUGHTER: "Gimme the bad first."
DOCTOR: "We're breaking up."
DAUGHTER: "Awww, what's the good news?"
DOCTOR: "I called the Family Planning clinic across town and they have a great big box of condoms for you,."

The moral of the story: "Protection" is a relative term.