 This increasing proportion of women who were too old to reproduce resulted in a greater variance in fecundity in the population of women, and it resulted in a greater sexual selection for indicators of youthful fecundity in women by men.The anthropologist Ashley Montagu said that the fetalized Homo erectus represented by the juvenile Mojokerto skull and the fetalized australopithecine represented by the juvenile "Australopithecus africanus" skull would have had skulls with a closer resemblance to those of modern humans than to those of the adult forms of their own species.Montagu further listed the roundness of the skull, thinness of the skull bones, lack of brow ridges, lack of sagittal crests, form of the teeth, relative size of the brain and form of the brain as ways in which the juvenile skulls of these human ancestors resemble the skulls of adult modern humans.