Differential reproduction for men and women.

There’s an idea I’ve seen a num­ber of times that 80% of women have had de­scen­dants, but only 40% of men. A lit­tle re­search tracked it back to this, but the speech doesn’t have a cite and I haven’t found a source.

The re­pro­duc­tion rates for men and women (pos­si­bly for the whole his­tory of the species) seems like the sort of thing which could be found out, but I’d like more solid in­for­ma­tion.