It is a difficult situation as folk have ownership of their own body so the State will have moral difficult opting to operate on someone without their express desire for it.
On the other hand there is a responsibility for not only the stream of children, which means one breeding machine can generate loads of welfare requirement from the taxpayer.
Surely there must be a point at which the demand on the public purse takes priority and the (ir)responsible parent has to be sterilised ?
It may well be that they are mentally deficient. Continually producing a stream of offspring without the means to support them does suggest this.
Meanwhile no one has the moral right, on an overcrowded planet, or even country, to produce more surviving offspring than they and their partner reduce the population by when they die. To do so means they are part of the global overpopulation problem, not part of the solution.