I'm not too sure where your question is aimed, if it's nuclear families I've got at least 2 with over 20 children, one a great uncle who had 3 families, two at the same time, if it's extended families I have masses of 24th cousins and I think more distant, courtesy of my Norman ancestry and their "courtesy" visit to England in 1066, traces back to people born in 870, Orkney, Germanic/Nordic principalities, and bits that are now French, like anyone else with those connections my extended family is huge.