Ordinarily the parentage of a child is acknowledged by both parents. The Family Law Act 1975 (Cth) contains a number of legal presumptions as to the parentage of a child.

The law presumes that:

Declaration of paternity

Disputes sometimes arise where there is a request for child support or a parent wishes to spend time with their child. If paternity is at issue in a matter before the court, either parent may ask the court for a declaration of paternity. A man seeking to refute a presumption of parentage must prove on the balance of probability that he is not the child's biological father.

DNA paternity testing

Parties contesting or asserting paternity can access DNA tests to establish paternity to the satisfaction of the court. DNA is made up of identifiable substances unique to each person, but which include some inherited from parents. DNA testing is accepted as the most definite proof of the physical relationship between humans. It is often referred to as a 'genetic fingerprint' and shows the links between individual body fluids in separate blood samples. The technique used to detect these links is known as DNA profiling. This technique is more effective than blood tests and blood typing because DNA can determine the identity of the parent to within 99.5% certainty as opposed to the process of elimination used in blood typing.

When will the court order DNA testing?

The court cannot order DNA testing unless it relates to existing proceedings. Orders for DNA testing cannot be made simply to satisfy the curiosity of a parent. They will only be ordered where they are needed to determine whether any parenting application is in the best interests of the child concerned.

Costs

Tests are done privately for a fee which varies between providers. Court orders for paternity tests are paid by the person who wants the results as evidence in their case. If a party receives legal aid, Legal Services may pay. The unsuccessful party will normally be ordered to pay costs. If there is no real doubt about paternity, applicants should be warned against baseless or vexatious applications, as they will be likely to pay the costs.