Average generation time is 26.9 years across the past 250,000 years, with fathers consistently older (30.7 y) than mothers (23.2 y), a disproportionate increase in female generation times over the past several thousand years

Human generation times across the past 250,000 years. Richard J. Wang et al. bioRxiv Sep 7 2021. https://doi.org/10.1101/2021.09.07.459333

Abstract: The generation times of our recent ancestors can tell us about both the biology and social organization of prehistoric humans, placing human evolution on an absolute timescale. We present a method for predicting historic male and female generation times based on changes in the mutation spectrum. Our analyses of whole-genome data reveal an average generation time of 26.9 years across the past 250,000 years, with fathers consistently older (30.7 years) than mothers (23.2 years). Shifts in sex-averaged generation times have been driven primarily by changes to the age of paternity rather than maternity, though we report a disproportionate increase in female generation times over the past several thousand years. We also find a large difference in generation times among populations, with samples from current African populations showing longer ancestral generation times than non-Africans for over a hundred thousand years, reaching back to a time when all humans occupied Africa.