It saddens me that mothers do this to their children. Why lie, it is better for all to be honest.
I don't feel the man should have to pay for a child that isn't his, unless he was aware prior to the child being born, that he wasn't the father and chose to stay.
I feel the child is the one who pays in the long run, they grow up being told this is your dad and then finds out later that he isn't, how emotional will that be for them. The man on the other hand, when he finds out, has to have some kind of resentment towards the mother, the resentment will fall on the child in some form or another, it's human nature.
You can't make someone love you, and that includes fathers who have been lied to. Why make them end up hating the child by forcing a financial burden on them.
The mother should be held responsible, financially. It should be her responsibility to also find the "real" father to provide financially and give him the option of getting to know his child.
The courts, should side with the father in these cases. With the mother being held accountable.