It's fraud on the mother's part...but they are very unlikely to suffer any consequences for extorting money from a man who isn't the father of their child.
There was a bill in California to help men who had been falsely named as fathers...Gray Davis vetoed the bill to please the NOW contingent.
In each case the child has a real father--why isn't he being asked to support his child?
Good question. I don't think we want to deny a child the love of a man he or she sees as their father if the man acts towards them like a father. Because human beings have managed to elevate love above mere biology. But in other cases where a man has no relationship with the child and isn't the father - is he still obligated to provide parental support? Justice and common sense say NO. When there is clear fraud perpetrated by one party upon the other, the party committing the fraud should not be allowed to benefit from the fruit of their crime. Period.
"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." - Manuel II Palelologus