Parental kinship is in our society conceived invariably and exclusively in terms of _consanguinity_,[519] or, speaking more explicitly, parental kinship is conceived as established by the tie of common blood, resulting from birth (maternal kinship) or procreation (paternal kinship). Of course the mere physiological fact does not establish kinship in its full extent, with all its personal, emotional, social and legal aspects. It is only when the physiological facts of procreation or birth are sanctioned by society, in other words when they are consummated in legal marriage, that the children are full kinsmen of both their parents. Society takes all facts which are of vital importance for itself under its own supervision; and consequently the important facts of propagation are subject to the control of society, which regulates them by a series of religious, legal, customary and conventional norms, all of which are also necessary conditions and essential features of full parental kinship. But this sanction once granted, the tie of common blood is conceived as the main source of all mutual duties and moral and legal obligations; and from this also outflow the feelings of love, attachment, reverence, and so forth, which are in our society the essential features of parental kinship. Once a man knows that a child, which he considered his own, is in reality not begotten by him, undoubtedly all his feelings for this child are affected, and, under certain conditions, its legal position may be modified. The two conditions for full parental kinship in our society are (1) that the child be the real physiological offspring of both presumed parents; (2) that it be legally begotten or its birth legalized. [519] Legal adoption being set apart as a case which only partly establishes the kinship relations. In our society the line of distinction between physiological consanguinity and social consanguinity is quite clear; the one is a mere physiological fact,[520] the other the social acknowledgment of this fact and all its consequences, subject to certain norms, laid down by society. [520] It seems hardly necessary to emphasize that for physiological consanguinity _as such_, pure and simple, there is no room in sociological science. There are two separate sets of circumstances in which we may speak of consanguinity: (1) the existence of social institutions, which allow us to trace the physiological blood ties (_e. g._ monogamy or harem institutions), in which case we can speak of the existence of physiological consanguinity as obtaining between the members of the individual family. (2) The existence of a social acknowledgment of the facts of procreation as creating ties of individual personal kinship, in which case we may speak of social consanguinity. If neither of these conditions are fulfilled, then it would be quite meaningless to speak of consanguinity.[521]