One may adopt a son permanently or for a short timc only. The son of the daughter (dauhitra) has then a double parentage. He has to offer funeral libations (tarpanas, pindas} and feed both the families in all religious rites. This is the view of Vasishtha. But Katyayana stated that it is not proper to perform the Shraddha for both. Vyasa, however, held that the grandson should perform the Shraddha of his maternal grandfather also, without any difference.