I would like to know which Act defines the rules about the determination of a father in Australia. I can find the rules on different websites, but not the source for which law it is.


Sometimes there is disagreement as to who is the father of the child. The law says that a person is the biological father of the child if:

Which law? Which act?

Same rules here: https://www.legalaid.qld.gov.au/Find-legal-information/Relationships-and-children/Child-support-and-maintenance/Proof-of-parentage#toc-disagreements-about-who-is-the-child-s-father-2

The law says a person is the child’s biological father if:

Which law?

  • You're citing one website from Victoria and one from Queensland, are you sure it's not different in each. If it's based on English & Welsh common law (which I think it possibly is) then it will be whoever has their name down as the father on the birth certificate. May 6, 2021 at 19:04
  • @GeoffAtkins It is almost certainly defined in a statue or regulation.
    – ohwilleke
    May 6, 2021 at 19:41
  • I am not an Australian Lawyer, but as far as I can see it is definitely similar to E&W common law. Later results trump previous ones; Marriage (including same-sex marriage) -> Name on an official instrument (parent listed on birth certificate) -> Convincing a court that's not right (contesting parentage through a court with DNA tests). That's based on the 1975 Family Law Act, but it's been modified a couple of times since then, most famously in 2017. May 6, 2021 at 20:04

1 Answer 1


The Family Law Act 1975 (Cth)

Specifically ss69P-69T create the following presumptions about paternity:

  • married to the mother
  • cohabitation with the mother
  • registered as the father
  • by finding of the court
  • by acknowledgment

These presumptions are rebuttable under the procedures spelled out in the subsequent sections.

  • thank you very much. I have searched a lot and did not find this :-) :-) :-) :-) May 7, 2021 at 22:34

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