There are plenty of real-world examples to illustrate this study's point. Consider, for example, that Hillary Clinton, Beyoncé, and Oprah are all the first-born females in their families. So, it's really no surprise we see so many fictional representations of this same idea. But, why are the oldest girls set up for such success? Feifei Bu, the study's lead researcher, says there are a couple of different explanations. "It could be that the parents simply devote more time and energy to them — it could be they are actually more intelligent," she told the Guardian. Though, she admits she feels "parental investment" is the primary reason behind this phenomenon.
For those who may feel discouraged by this information, take solace in the fact that the first-born girls often receive the strictest upbringing. And, they'll never stop reminding you of that. (Jezebel)