GeneaNet now use the Sosa-Stradonitz System, also know as Ahnentafel or Kekule, for numbering ancestors on your online family tree.

GeneaNet - les numéros Sosa

Your family tree root (Sosa 1) has been automatically calculated but you can easily change it.

Then, just select the D, F, H or I online family tree template to show Sosa-Stradonitz numbers on your family tree pages.