Are parents altruistic or selfish? We contribute to the continuing debate of this question by proposing a simple test which is implemented using experimental data from the Mexican anti-poverty programme PROGRESA. Benefit eligibility is randomised. Our estimation strategy explicitly addresses potentially confounding factors and selection bias problems. We reject selfish- ness of parents in non-urban Mexico as PROGRESA beneficiaries spend more on child-related goods and do not increase spending on adult-related goods compared to parents in the control group. At the same time, we reject some rival theories.