Inclusion criteria: i) Infants of both sexes born to vaginal/caesarean delivery; ii) Gestational age: 37-42 weeks; iii) Italian-speaking parent; iv) 7 Ability of the parent/guardian to give informed consent; v) Ability of the mother to answer questionnaires. Exclusion Criteria: i) Infants with genetic/congenital diseases; ii) Infants selected for another clinical study; iii) Infants hospitalized immediately after birth; iv) Presence of gestational diabetes; v) Presence of hyperthyroidism during pregnancy; vi) Parents refusing to sign the informed consent.