THE FIRST SENTENCE BEGINS "ROSE'S EXIT FROM DOCTOR WHO"
SERIOUSLY, IT'S THAT SPOILERY.
Rose's exit from Doctor Who is unusual, not just in Doctor Who but as a rite of passage in general, because it's a rite of passage back into the arms of her family and back into childhood. Most other memorable female companions -- most notably Susan, Jo and Leela -- leave for romantic reasons. Of the more minor ones, Tegan leaves out of weariness, Mel leaves for frankly no good reason, Nyssa and Romana leave for romance-slash-destiny, Peri either dies or gets married. And of course poor Sarah Jane gets kicked out onto the street and ends up bopping a dog with a tennis racket out of frustration.
But Rose goes back to her family, goes back to her boyfriend, and three years later it isn't even her who's pregnant, it's her mother. It's a weird message for a family show: that the goal is not to grow up but to get back where you came from.