Most Likely to Succeed: Firstborn Girls They lead in both achievement and ambition, study says By Rob Quinn, Newser Staff Posted May 2, 2014 1:02 AM CDT 7 comments Comments Oprah Winfrey smiles before being awarded the Presidential Medal of Freedom. (AP Photo/ Evan Vucci, File) (Newser) – Bad news for younger siblings and firstborn boys: Firstborn girls are most likely to end up running the world. In a new study, British researchers found that eldest children tend to be both more ambitious and more successful than younger siblings, and firstborn girls are 13% more likely to aspire to higher education than firstborn boys, Scientific American reports. Powerful firstborn girls include Hillary Clinton, Angela Merkel, Sheryl Sandberg, and Oprah Winfrey. "There are several explanations for the higher attainment and ambition of the eldest," the lead researcher tells the Guardian. "It could be that the parents simply devote more time and energy to them—it could be they are actually more intelligent. For me, I tend to lean towards the theory that parental investment is possibly at work here." She says she has a personal interest in the research because "I'm the firstborn, of course. That is why I'm doing a PhD."