In late 2011, an Expert Panel convened by the National Heart, Lung, and Blood Institute (NHLBI), of which we were members, released a set of integrated guidelines for cardiovascular health in youth comprising numerous clinically useful recommendations.1 However, one new recommendation, about which the 2 of us disagree, merits further scrutiny: to perform lipid screening on all children at 9 to 11 years of age, followed by a comprehensive scheme for further evaluation and treatment. Just 4 years previously, the US Preventive Services Task Force (USPSTF) concluded that evidence is insufficient to recommend for or against screening for lipid disorders in childhood.2 Both of the guideline committees used an explicit evidence-based approach to answer key questions, with extensive literature searches, critical review of relevant studies, and analogous grading schemes. How could the 2 guidelines be so different? The evidence base has advanced in 4 years, but not enough to explain such a discrepancy. What is a clinician who cares for children to do in the face of this ambiguity?