Gens (Nova Roma)
Membership of a gens is hereditary: a Roman child is in the gens of his or her father. Some ancient gentes claimed that all their members were descended from a common ancestor, but this was perhaps never true; in any case it was not true by the middle of the ancient republic, and is certainly not true today.
Nonetheless, in ancient times many noble gentes maintained close internal ties of kinship and support, and members of the same gens were often political allies. Many gentes also had shared religious traditions (sacra gentilicia), and it was socially unacceptable for members of the same gens to marry.
A gens is further divided to branches (stirpes) which are in Nova Roma - mistakenly - called domús. A domus (or more correctly: stirps) includes all members of the gens who share the same nomen-cognomen combination: for example, Cn. Cornelius Lentulus Maior, Cn. Cornelius Lentulus, and L. Cornelia Lentula are all Cornelii Lentuli, or members of the domus Cornelia Lentula. Members of the same domus are officially considered real blood relatives by Nova Roma, brothers, close or distant paternal cousins. A new citizen who wants to take the nomen-cognomen combination of an already existing domus, can only do so if a majority vote of the members of the domus allows him to take the name of the domus, and acknowledges him as a real relative. Membership of a domus is hereditary: a Roman child is in the domus of his father.
The domús are divided to families, headed by a pater familias (father) or a mater familias (mother) who act as the leaders of the family and speak for it when necessary. The holders of this position must be registered as such with the censors. The pater familias or mater familias may, at his, her, or their discretion, expel members of his, her, or their family, accept new members into it by adoption, or allow members to form new Nova Roman families belonging to the same order (patrician or plebeian)
Families are the basic operating units of Nova Roman society, each family having the sacred and inalienable right to self-government, to their own identity and cultural family traditions, religious or otherwise.
Families being the backbone of Roman society, the prerogatives and responsibilities of the familia are of primary importance to Nova Roma. Each family has the right to determine its own course of action and parents shall have the undisputed right and responsibility to see to the education and raising of their children.