What happens when your previous partner says, “I don’t believe that child is really mine”. Of course, there are a great deal of emotions during separation. Even where there was never infidelity, the question of parentage can be raised by the other party out of hurt feelings. Other reasons might be that a claim is made for the payment of child support.
The person questioning the paternity of a child have not considered how that question could affect the child in question. If the child is well into teenage years or a pre-teen, the relationship of parent/child is well established. The question we would pose to the person wanting the test is “have you considered the child and how they will react?” How will you explain your reasons for the testing to the child? and “what is it that you will do if they are not your child?”. When a parent has been a parent for a long time, do they want to sever that relationship? Are they proposing to remove that child from their life? What will happen in the event that the child is not yours?
These issues must be considered before asking for or agreeing to the DNA test.
Be aware that proper DNA testing isn’t taking a hair from a hairbrush and sending it to a lab. It requires a blood test from a child which is usually traumatic in itself but how will it be explained to an older child/teenager as to why this test is required?
The court take a strong view in relation to parentage testing and say that there must be evidence to put parentage in issue – mere doubts are not sufficient.
The starting point is the presumption of parentage under the Family Law Act.
For married couples, under section 69P, if a child is born to a woman while she is married, the child is presumed to be a child of the woman and her husband.
For de facto couples, under section 69Q, is that if the child was born to the woman AND at any time during the period beginning not earlier then 44 weeks and ending not less than 20 weeks before the birth, the woman cohabited with a man to whom she was not married then the child is presumed to be a child of the man.
Further, there is a presumption that if a person’s name is entered as a parent of a child in a register of births or parentage information then the person is presumed to be a parent of the child (s69R).
Further, there is a presumption as to artificial conception procedures under s60H(1).
There appears a vast amount of presumptions and the onus is on the person who says the child is not theirs, to rebut that presumption. However, case law has very much made it clear that parentage is no longer determined by legal presumptions. In G v H  FamCA 39; (1993) FLC 92-380 Fogarty J noted at 79,942: “Paternity is now a medical and not a legal issue.”
A DNA test will confirm paternity, not 100% but with such a strong likelihood of paternity that it can be said legally that the child is the child of the father. A DNA test will exclude a person being the father of a child with 100% certainty. It is a very simple answer to the question of paternity to do the test.
But firstly, consider the child.