The word “Santhathi” is wide enough to include natural as well as adopted children. [(1916) 1 MWN 306]

The etymological meaning of ‘Santhathi’ is ‘issue of the body’ the expression ‘Santhathies Paramparai’ used as a word of limitation to define the estate taken by a person has, however, come to acquire the larger significance of ‘heirs’. [AIR 1954 Andhara 2, 4 quoted in P Ramanatha Aiyer’s The Law Lexicon]