 Homo sapiens is known from fossils to have had a mix of modern neotenic traits and older non-neotenic traits from its origin some 300000 years ago to the transition to early agriculture when the non-neotenic traits disappeared, which is theorized to be due to selection for the immune system adapting to survive a higher pathogen load caused by agriculture and men who retained more childlike traits being less burdened by weakening of the immune system from upper body musculature competing with the immune system over nutrients.It is argued that the genetic evidence of only a small part of the male population of the time of early agriculture passing on their Y chromosomes can be explained by the heredity of non-neotenic traits causing the male descendants of the non-neotenic men who were not killed by diseases in one generation to die from them in subsequent generations, leaving no Y chromosome evidence of their short term continuation of paternal bloodlines in present humans.Sexual selection for stereotypic masculinity causing most men to fail to breed is ruled out as it would have selected against neoteny, not for as the archaeological evidence shows.