Dr. Falbo uses both quantitative and qualitative techniques to deepen our understanding of human development, particularly considering the impact of siblings on physical, academic, and social outcomes of children and adults. She has collected and analyzed data from China, Guatemala, Korea, and, of course, the U.S. Recently, she completed research studying sibling effects on body mass index (BMI) and found that lacking siblings is associated with higher BMI, an effect that persists from adolescence to middle age. In addition, Dr. Falbo has been studying the reasons why Americans avoid having solely one child, using both quantitative and qualitative data. Quantitative data analyses of responses collected from UT undergraduates indicate that planning to have no children or just one child leads to social criticism, because parents are expected to have at least two children. Qualitative data analyses indicate that choosing to have just one child is thought to lead to that child's loneliness; nonetheless, UT undergraduates understand that financial limitations may lead some couples to stop at one. Dr. Falbo plans to continue her research about the influence of siblings on child and adolescent development, and the benefits and costs of sibling relationships across the life course.