Almost 20 years ago a mother and her three-year-old daughter stood outside the High Court with a placard that read: “Mum, can women be High Court judges?”

Mary Gaudron, the first and only woman to serve on the court, was retiring. Dyson Heydon was being sworn in that day – February 11, 2003 – as her replacement. Many people, including the next judge to retire, were asking the same question.