Are adopted children obligated to search for their biological parents so they can honor them? The Talmud implies that an adopted son is not obligated to honor his adopted parents: "Rabbi Aha ben Yaakov raised his daughter's son, Rabbi Yaakov. When he grew up, [the grandfather] said to him: “Give me some water to drink”. He replied: “I am not your son.”" [Sotah 49a] But the Midrash says: "He who brings up children is called the father, not he who gives birth." [Ex. R. 46:5] So who should adopted children honor, per halacha?