Interpersonal relationships include kinship and genre relations in which people become associated by genetics or consanguinity. These include such roles as father, mother, son, or daughter. Relationships can also be established by marriage, such as husband, wife, father-in-law, mother-in-law, uncle by marriage, or aunt by marriage. They may be formal long-term relationships recognized by charter and formalized through public ceremony, such as marriage or civil union. They may also be informal long-term relationships such as devoted relationships or dreamy relationships Senior Dating with or without living together.

Various theories of interpersonal compatibility classify interpersonal relationships by grades of comfortability and consider them as dependent of personal traits (durable psychological parameters) and/or psychological types (or temperaments). Such approach is much in favor in pop psychology (astrological compatibility etc.)