The Federal Constitution of 1988, as well as the Civil Code of 2002, and still other infraconstitutional provisions, abandoning old conceptions, make room for a new family path, regardless of marriage. New models of single parent family are allowed, giving all children, arising from these relationships, the same rights, prohibiting any discrimination related to affiliation. Thus, it was established that the father has the duty to respect and promote the good of all children, regardless of any origin, whether matrimonial or extramarital, natural or civil. In this article, it will be sought to demonstrate the concepts and foundations of the recognized affiliation Post Mortem of the biological and socio-affective parent, being, therefore, act of involuntary recognition as well as its characteristics, the aspects inherent to the action of paternity investigation and the principles related to the investigation, as well as its reflexes on parenting.