My son was raised with an older sister. He learned skills like reading, playing quietly, conversational play, and social eating (aka tea parties).
My little girl is being raised with an older brother. She's learning skills like crashing vehicles, saying "fart" and "butt" as often as possible, and eating bizarre combinations of food.
Having a boy-with-big-sister was far, far less embarrassing than having a girl-with-big-brother.