Scholars have argued that children affect their parents’ political behavior, including turnout, through so-called trickle-up socialization. However, there is only limited causal evidence for this claim. Using a regression discontinuity design on a rich dataset, with validated turnout from subsets of Danish municipalities in four elections, we causally identify the effect of parenting a recently enfranchised voter. We consistently find that parents are more likely to vote when their child enters the electorate. On average across all four elections, we estimate that parents become 2.8 percentage points more likely to vote. In a context where the average turnout rate for parents is around 75%, this is a considerable effect. The effect is driven by parents whose children still live with them while there is no discernible effect for parents whose child has left home. The results are robust to a range of alternative specifications and placebo tests.