Many countries are strengthening their regulation of the gambling industry. Measures to protect children from exposure to gambling are often an important component of regulation, as childhood exposure to gambling is thought to lead to problem gambling (PG) in adulthood. We report a pre-registered analysis of survey data from a nationally representative sample of adults in Ireland (N = 1,663). Almost two-in-three adults (64%) report having gambled before turning 18 and doing so is associated with an 83–87% increase in the risk of later-life PG (p < 0.01). Having a parent who gambled and having parents with more positive attitudes toward gambling are also associated with increased risk of PG of 33% (p < 0.05) and 31–40% (p < 0.05), respectively. Those who had a parent that gambled a lot are 80% more likely to have PG (p < 0.01). However, the relationship between parental behavior and PG is weaker among younger age groups. Having multiple childhood risk factors is associated with between a doubling and a quadrupling of the probability of PG. Our findings support child-focused regulatory measures to restrict access and exposure to gambling for children.