Under Zimbabwean common law, the mother of a child born out of wedlock is the sole guardian of that child with exclusive rights of guardianship and custody. A customary union that is not a valid marriage under the Customary Marriages Act results in children being born out of wedlock for common law purposes. Section 3(5) of the Customary Marriages Act, which recognizes certain rights of fathers under customary law, does not apply to matters governed by statute and common law such as birth certificates, passports, and visas. Under section 18(3) of the Births and Deaths Registration Act, where a child is born out of wedlock, the mother is the 'responsible parent' with sole authority to change the child's surname through notarial deed, and the Registrar has a mandatory duty to register such change upon compliance with statutory requirements without requiring the father's consent.