The present article offers a commentary on two passages from the Gnomon of idios logos: § 41 (BGU V 1210, ll. 115-116), which pertains to a quarter of the inheritance left by an Egyptian who adopted a child picked up from a dump-hill, and § 107 (BGU V 1210, ll. 238-239), which repeats the same rule with regard to everyone, regardless of their civic status. The following problems are subject to our investigation: 1) Which specific type of adoption was expressed by the verb υἱοποιέομαι in § 41? 2) Why does the adoption of foundlings not appear in documentary sources? 3) What was the scope of the cited provisions? The article offers a survey of the legal status of exposed children and (im)possibilities of their adoption in law and legal practices in Roman, Greek and Egyptian sources.