What did the family have to do in order for Gabriel to be allowed a second year of nurturing in The Giver?

Jonas's Dad goes and requests a plea for Gabriel. Then the family signs a 'contract' to say that they will not become attached to little baby Gabriel. Also the fact that Gabriel had pale eyes like The Giver, Jonas, Rosemary(The previous receiver & The Giver's daughter) might have contributed to the fact that Gabriel was allowed a second year of nurturing.