On The Estate of Apollodorus (16)

Now these bodies have a uniform rule, that when a man introduces his own son or an adopted son, he must swear with his hand upon the victims that the child whom he is introducing, whether his own or an adopted son, is the offspring of an Athenian mother and born in wedlock; and, even after the introducer has done this, the other members still have to pass a vote, and, if their vote is favorable, they then, and not till then, inscribe him on the official register; such is the exactitude with which their formalities are carried out.