Paternity Definition: Being a father. Being a father. The legal acknowledgment, recognition or declaration that a male person is the natural father to another. Paternity suits are launched when a man denies paternity of a child born out of wedlock (and sometimes even when the child is born during the marriage!). New technology of DNA testing can establish paternity thus obliging the father to provide child support. Categories & Topics: Family Law Dictionary Find you are constantly looking up definitions? Try our search provider (works in most modern browsers) If you find an error or omission in Duhaime's Legal Dictionary, or if you have legal term suggestion, we'd love to hear from you!