On the Relationship Types tab of the Relationship Settings page, you can manage the relationship types used with your constituents. For example, your organization may specify that a relationship type of Brother applies to only the male gender, or that Sister applies only to the female gender. You can also specify the types of constituents the relationship type applies, along with the types of constituents who can have relationships of this type. For example, a relationship type of Employee might apply to only individuals—that is, only individual constituents can be considered as employees.
When you add relationships to constituents, you specify the reciprocal relationship. If you add a relationship type of Father to a constituent, the reciprocal relationship might be Son or Daughter. The most common relationship pairs become the default reciprocal relationships. If your organization has more father/daughter pairs than father/son pairs, the default reciprocal relationship when you add a relationship type of Father is Daughter. However, you can still select Son or any other value for the reciprocal relationship.