I am predicting that sexually reproducing species with males having a lower genetic diversity in their genome than females, like in humans and, likely in chimpanzees, with their Y chromosome bearing less genes, will be constituted of males reproducing nearer their birthplace and of females reproducing farther their birthplace, a higher genetic diversity is necessary to enter new environments and reproduce successfully because of pathogens infecting males and females entering new environments who might not be adapted to resist such pathogens of new environments (see Hamilton, W.D. (1982) Pathogens as causes of genetic diversity in their host populations. In R.M. Anderson, R.M. May (ed.) Population Biology of Infectious Diseases, pp. 269-296. Springer, New York). From my personal observations on a human population that should be published in a near future, human males of a population were marrying farther from their birthplace than females, but in a distance enabling them to resist pathogens, which is less common for a human population (see Seielstad, M., Minch, E. & Cavalli-Sforza, L. (1998) Genetic evidence for a higher female migration rate in humans. Nature Genetics, 20, 278–280). I am actually reflecting on my observations, such an article on chimpanzees, humans and patrilocality is useful for my reflections.