Sayyiduna Uthman bin Affan (may Allah be pleased with him) said: "Whoever gives a gift to his young child who has not yet reached the age of taking possession, and announces it and appoints witnesses to it, then it is valid, and his father is its guardian."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الهبات / 11952
Sayyiduna Umar (may Allah be pleased with him) said: "What is the matter with people who give gifts to their children, and when one of them dies, he says: 'My property is with me,' and if he himself dies, he says: 'I had given it to my son'? There is no gift except a gift that the child takes possession of, apart from the father; then if he (the father) dies, it becomes part of his (the child's) inheritance."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الهبات / 11953
Sa'id bin al-Musayyib (may Allah have mercy on him) said: That was complained of to Sayyiduna Uthman (may Allah be pleased with him), and he held that the father takes possession on behalf of his children when they are young.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الهبات / 11954