I think we'd all probably consider it desirable that children get to go to school and to go out and play rather than have to labour for their bread from an early age. However, quite how we achieve that wondrous state is something that is more contentious. For there's good evidence from India that simply making child labour illegal increases the amount of it that happens.
There are many policy options to readdress this. Bans and regulations against child labour are among the most popular worldwide. When perfectly enforced, bans force employers to forgo the use of child labour. However, it is not clear that such laws will always lead to reductions in child labour. In reality, governments in countries where child labour is prevalent, rarely have the capacity and resources to perfectly enforce regulations on child employment, as documented in a recent study by economists Eric Edmonds and Maheshwor Shresthra (2012). According to a simple model by Kaushik Basu (2005), when bans are imperfectly enforced, they raise the cost of hiring children, as employers anticipate facing stiff fines or other penalties when caught using child labour. Thus, when imperfectly enforced, bans may simply lower the wages that children are paid. If families send their children to work out of necessity, this can have perverse effects, as it lowers the income for families relying on child labour. Therefore, a drop in child wages may compel families to supply more child labour, rather than less.
If the entire brood is starving then you might send one or two out to work and try to educate the others. But if that ban on those first two leads to their wages dropping you might need to take all of them out of school. And it is very much this sort of effect that they've found.
We might say that this could be solved just by perfect implementation of the law: well, good luck with that among India's 1.2 billion people.
My own opinion on this is that many of the things that we consider desirable aspects of society, no child labour, the economic emancipation of women, education, shorter working hours and so on, they're the results of an increase in economic wealth, not a cause of it. Sure, there's something of a feedback going on but it's being rich enough to not need the child's paltry wages that leads to their being educated. That child mortality rates fall (an excellent example of people very definitely getting richer that doesn't necessarily show up in monetary of GDP figures) so that women can do something else with their lives rather than just pump them out. That there is that surplus available to invest in education, that again there is that surplus available to even have the concept of leisure, it is this that drives the improvements we wish to see. Not the passing of laws that insist we must have these things, or stop doing them, but that as wealth increases we can afford not to do the undesirable things and also afford to do the desirable.
It's growth first in other words.
*Whatever it is that this phrase actually means.