The conservativeness of the SAM (Specific Anthropomorphic Mannequin) phantom for the SAR (Specific Absorption Rate) evaluation in the child's head is investigated. Five head models representative of the adult human population are selected from forty 3-D laser-scanned head models of volunteers for numerical simulations using a generic mobile phone model. A child's head model is derived from the visible human head model using a morphing technique. Numerical simulations are undertaken for the four intended use positions using three excitations - dipole antenna, monopole antenna mounted over a metallic box and PIFA (Planar Inverted-F Antenna)-based mobile phone - at the three frequencies corresponding to the currently used mobile communications systems. All results are compared with those obtained using the SAM phantom. Overall the calculations show that the SAM phantom is conservative for the SAR evaluation in the child's head.