This interview explores current controversies in the management of hypothyroidism in children. Newborn screening programs have allowed early detection and treatment of babies with congenital hypothyroidism, but some programs do not detect cases with delayed thyroid-stimulating hormone (TSH) elevation and most do not detect congenital central hypothyroidism. Lack of harmonization of TSH cut-offs means that some programs do not detect milder cases of congenital hypothyroidism.