Sauce for the goose is not always sauce for the gander. If you're the biological mother of a child, you know it. If you get pregnant and the child is born, no one can dispute that you were a biological parent. Fathers, on the other hand, don't have it so easy. If paternity is disputed, a man must wait until the child is born to do DNA testing, and, even when he is found to be the biological father, the court can declare someone else the legal father. Unraveling the story starts with a paternity test, which can be done at no cost through a local child support agency.

Not every couple having a child seeks paternity testing. The typical husband assumes that if his wife bears a child, he is the father. And in many states, the law presumes that the husband of a married, pregnant woman is the child's father. This is often a conclusive presumption that cannot be disproved even if you produce evidence disproving it.

Most paternity issues arise when the parents are not married, the child was not expected and the person the mother names as the father has reason to believe he is not the only possible candidate. If the child's mother goes to the child support agency and asks them to file an action for child support against you, you can at that time request free paternity testing.

In some states, the same state agency that collects child support offers free paternity testing. In California, for example, the local child support agency will seek child support from the man a woman names as the father of her child. If she applies for government assistance for herself and the child, the aid agency requires that a child support complaint be brought.

Once the child's mother provides your name, you are served with a complaint seeking child support. From the date someone hands you the legal documents, you have 30 days to respond. In the response, you can say that you are not the father. This is also the time to request a paternity test. If you do not respond within the three-day period, the court may issue an order naming you as the legal parent without a paternity test.

Similar laws are in place in many states. In Arizona, for example, the state will pay for the alleged father's genetic testing necessary to determine paternity. If you are found not to be the father, you pay nothing. If you are found to be the father, you can repay the test costs in installments. This is also the situation in Alaska.

In Missouri, the Family Support Division of the Missouri Department of Social Services offers free paternity testing in cases where paternity has not been established. In Louisiana, if either party is on public assistance, the state will pay for paternity testing.

If you don't live in a state that offers free paternity testing, someone will have to pay for it. Look around to see if you can find low-cost testing at a public clinic.

Many home paternity testing kits are available at low cost off drugstore shelves. However, these are rarely accepted by family law courts as conclusive genetic testing. On the other hand, it may be a good place to start.