Two recent issues of Pediatrics contain significant contributions to our knowledge of fetal growth as derived from birth weights at various gestational ages,1-3 and a comment by Tanner4 which is of particular interest because it comes from an expert viewing growth in a broader perspective than just the fetal period. The following comment will be limited to the early part of the third trimester when differences between reported data can be reconciled by correction. This is in contrast to differences between populations late in the third trimester; for instance, the recent reports of Babson, et al.1