I feel there is a need for an Add Parent option?

You have provided options to add partners, add brothers and sisters, add children but there is no add parent option when I am editing a family tree.

Without the add parent option it is not possible to extend a family tree upwards when I want to add extra nodes.

The alternative would be to provide the option to create a new, unattached node on the family tree. Then provide the option to attach the node to another node on the tree (as a parent, partner, brother/sister or child). My guess is that this option would perhaps be more complicated than having an add parent option.