Evans et al. and Mekel-Bobrov et al. (Reports, 9 September 2005, p. 1717 and 1720, respectively) reported that human genetic variants of Microcephalin (MCPH1) and abnormal spindle-like microcephaly associated (ASPM) are under strong positive selection. We genotyped these variants in 9000 children and find no meaningful associations with brain size and various cognitive measures, which indicates that contrary to previous speculations, ASPM and MCPH1 have not been selected for brain-related effects.