While it may seem like paternity is only an issue for those who have never been married, it is really at the heart of any child custody issue. Many people are surprised to find out that even if a child is not biologically theirs, they may still have to pay child support. It's important for those going through a divorce with children to understand how the presumption of paternity works and why it matters.
If a child is born during a marriage or within a certain time frame after a divorce has been initiated, the husband is usually assumed to be the father. This is called a presumption of paternity. Even if both the mother and the man are aware that the child is not biologically the husband's, it can be very difficult to get the courts to release the husband from obligation of financially supporting the child.
In many cases, however, the husband never knows that the child is not biologically his until much later on, sometimes even years. It's not uncommon for those going through a divorce to suddenly demand a DNA test just to "double check" that the children are theirs. Unfortunately, this is usually after the time period in which paternity can be challenged has passed, meaning the man will likely still be responsible for paying child support even if the DNA test shows he is not the father.
Because these situations can be very complicated, it's important to have an experienced family law attorney who can help guide you through the process. By doing this, you can be sure you are aware and informed of all of your rights and options.
Source: Women Against Paternity Fraud, "What is Paternity Fraud?," accessed March 04, 2016