People with brothers make for better lovers.
After living with my sister for over a year in a cramped railroad apartment in New York City, I can attest to the fact that boarding with a sibling is a patience-building, character-strengthening experience, and if I'm anything like a fly, it probably made me a better lover.
A study from the University of Oxford has found that flies who live with their brothers cause less harm to females during courting and mating. Flies shacked up with unrelated flies, on the other hand, compete more aggressively for the attentions of their lady bugs, which shortens the male's lifespan and stresses the females out enough to reduce their fertility. Bro flies don't get as feisty towards their dates because they think to themselves, "Whatever, at least someone in my genetic line is going to propagate the species." It's pretty much an evolutionary fistbump.
Probably the only thing I have in common with a fly is the fact that both of our mating patterns involve singing and genital licking, but I also think there's something to be said for siblings making us gentler, better lovers. Who, after having a rock thrown at the back of their head at the beach resulting in stitches, is not also prepared to spend nights surviving their lover's office party? And being knees-to-chest cramped with three children (one, vomiting) in the back of a Sedan on your way to Myrtle Beach can teach you a lot about sharing a full-sized bed in a long term relationship. Having your brother urinate in his sleep on your brand new Simba comforter? You now have the wherewithal to compromise with your boyfriend about his hideous sweater collection. Through having siblings, we learn to put other's emotional needs if not above ours, then at least on the same level.
Having siblings prepares us for other complicated relationships in our lives, namely marriage. Siblings and spouses have one huge thing in common: you share everything. Grapes, a closet, a diarrhea-inducing virus. This has been studied before, as researchers at the American Sociological Association found that having siblings greatly reduces the chances you'll get a divorce. And if your mom popped out a few more kidlings, each additional sibling reduces the likelihood of divorce by two percent. That's because growing up in a larger family makes you a master negotiator and communicator. Your long arguments about why you deserve the last tater tot prepare you for larger marital conflicts like budgeting, how to raise your kids, and who watched ahead on Breaking Bad.
I am by no means saying that sibling-having individuals are superior to only children (some are), but I am saying that the next time Bobby Brady over at your local bar goes on and on about his sister Marcia's new veterinarian's degree, don't start to inch away fearing he is a little too family-oriented. Know that what he's really saying is, "I will generously and frequently go down on you shortly after preparing a nutritious homecooked meal." He always had to put the ladies first, that's just how he was raised.