An international study by researchers from the University of Leipzig, the University of Zurich and Victoria University of Wellington, New Zealand found that our personality as adults is not determined by whether we grow up with sisters or brothers. The results have now been published in the renowned journal “Psychological Science”. Siblings play a central role in childhood, and so it seems reasonable to assume that they influence each other’s personalities in the long run. In fact, psychological research is tackling the question of whether it makes a difference whether people grow up with sisters or brothers for more than half a century. To shed light on a previously inconsistent data situation, a team of researchers has now analyzed data from more than 80,000 adults from nine countries, including Germany and the US, also Mexico and China for example. This was made possible by various national longitudinal studies that systematically collected information about people over the decades, including their living conditions and personality traits determined in various ways. Statistical analysis of this data showed across national boundaries that personality traits such as risk-taking, emotional stability, conscientiousness, and patience are not systematically related to sibling gender.