firstborns tend to be “ambitious, conscientious, and achievement-oriented.” But before concluding that these are good things, note, please, that firstborns also tend to be “more conforming, conventional, and defensive,” as well as, for good measure, more “dominant, aggressive, . . . jealous, and conservative.” Laterborns, on the other hand, tend to be more flexible and tolerant as well as “more altruistic, empathetic, and peeroriented,” more adventurous—more inclined to engage in contact sports, foreign travel, exploration—and more sympathetic to underdogs.