Since the turn of the millennium, DNA testing has helped with establishing the sizes of biological descent families within surnames. Some surnames have a dominant family: their remaining populations can be ascribed either to NPEs (non paternity events)or to smaller separate-origin families. Previously, there was no direct evidence as to how large each male-line family could grow within a surname, considering that real-life plural-origin surnames could contain a few or many separate-origin families of various sizes. However, DNA testing is providing evidence to help indicate in particular the size of the largest male-line medieval descent family in a surname. We here perform statistical analyses of some relevant DNA results. This allows us to compare the DNA results with some predicted findings from our computer simulations.