Gabel F, et al. - Using a Two-Stage Least Squares (2SLS) instrumental variables approach and large-scale cross-sectional data from the Survey of Health, Ageing, and Retirement in Europe, researchers investigated the causal relationship between the number of biological children and their parents’ number of missing natural teeth. Outcomes revealed a strong causal association between the number of children and teeth for women but not for men when an additional birth occurred after the first two children had the same sex. Thereby suggesting a detrimental effect of an additional birth on the mother’s but not the father’s oral health.