William was born in 1883. He is the son of Janet Anderson.
Sources
Birth Registration: "New Zealand Births, Deaths & Marriages Online", (digital index), New Zealand Department of Internal Affairs. ; Reg No. 1883/18413 Beattie William Ernest, Janet & Robert
Marriage Registration: "New Zealand Births, Deaths & Marriages Online", (digital index), New Zealand Department of Internal Affairs.; Reg No. 1911/4496 Jessie Elliott & William Ernest Beattie