We have had several requests for step-parents to appear in the parent directory. Since "step-parent" is not a role and it is just a relationship type, there is no way to have them appear in the directory. Please create a "step-parent" role that allows us to use the step-parents in a more functional way in the system (think similar to grandparent).
Since not all step-parents are actively involved in their step-child's schooling, having the option to activate certain things for step-parents would be ideal.