When Paul and Leanne needed a surrogate mother, Leanne's own mother, Antoinette, stepped in to help. The baby that resulted—a boy named Kye—is legally his mother's brother.
Victorian law demands the birth mother and her partner are registered as parents.
Antoinette's husband, David – Leanne's father – is registered as Kye's father and Leanne is legally considered Kye's sister. His biological father, Paul, does not rate a mention.
Leanne and Paul would need to adopt their own son to have his birth certificate amended – but even this is not allowed under Victorian law. [Link]