This depends where you live of course but in general, Child Support is fair in concept because a child needs to be cared for and its parents are primarily responsible for it. What<is> unfair is that the amount the working parent (usually the guy) has to pay. It's calculated as a percentage of his income, offset by the wife's income over a minimum amount. The courts recognise that mothers cannot easily find full time employment when looking after a young baby/child but as the husband simply pays more if the wife is not earning enough, she is obviously dis-incentivised from working at all. Added to this, the court does not recognise any other children (e.g. from a second relationship) that the husband may also have responsibility for, so those children are unfairly financially penalised. Also, child support payments are percentage based on a man's income. The more he earns, the more support he pays. This goes against the principal that a child only needs a finite amount of money to guarantee its well being, so this percentage of income test further penalises the man and dis-incentivises him from working. A lot can change in a man's career in 18 years. Child support also does not fully consider that the husband also contributes to the care of the child while it is in his custody, so he is essentially paying twice. In short, good idea in principal but broken and abused like most other social welfare programmes.