This paper studies whether sibling gender affects personality traits. We use the idea that if parents decide to have a second child, it is random whether they will have a boy or a girl. Therefore, the relationship between the second-born sibling's gender and the first sibling's personality traits is causal. We employ longitudinal data from a large British cohort which is followed from birth onwards. The dataset includes personality traits at age 10 and 16. Our main result is that oldest boys in a household are more agreeable if their next-born sibling is a girl. This effect is robust across age (10 and 16), when controlling for among others family size, and when applying corrections for multiple hypothesis tests. Agreeableness is an important trait in life as it has been shown to correlate positively among others with being employed, having a skilled job, savings, and life satisfaction.

本文研究同胞性别是否会影响人格特质。我们的想法是，如果父母决定生第二个孩子，那么生一个男孩还是一个女孩是随机的。因此，第二胎兄弟姐妹的性别与第一胎兄弟姐妹的人格特征之间的关系是因果关系。我们采用了来自大型英国队列的纵向数据，此数据从出生起就一直遵循。该数据集包括10岁和16岁时的人格特质。我们的主要结果是，如果家庭中年龄最大的男孩的下一代兄弟姐妹是女孩，则他们更容易相处。当控制其他家庭规模时，以及在对多个假设检验进行校正时，这种效应在整个年龄段（10岁和16岁）都是很稳定的。和gree可亲是生活中的重要特征，因为它已被证明与受雇者之间呈正相关，