S4 Family Law Act 1975 (Cth) defines a stepparent as a person who:
- Is not a parent of the child;
- Is, or has been, married to or a de facto partner of, a parent of the child; and
- Treats, or at any time while married to or a de facto partner of the parent, treated the child as a member of the family formed with the parent.
A de facto relationship includes same sex couples.
Stepparents are legally defined as a ‘relative’ of the child and are therefore able to make an application to the Family Law Courts pursuant to the Family Law Act.