There's a method to estimate that: http://en.wikipedia.org/wiki/Most_recent_common_ancestor#MRCA_of_all_living_humans http://en.wikipedia.org/wiki/Most_recent_c

There's a method to estimate that: http://en.wikipedia.org/wiki/Most_recent_common_ancestor#MRCA_of_all_living_humans http://en.wikipedia.org/wiki/Most_recent_common_ancestor#MRC... "Studies have used computer modelling to estimate that the MRCA of modern humans lived between 5,000 to 2,000 years ago."