Child labor does exactly what is says on the tin. It is the use of workers under the age of 16 to do tasks that would otherwise be allocated to unfortunate adults. The word labor of course suggests that the tasks these children have been provided are physically strenuous such as mining, farming of repetitive factory work. These jobs are described as being in the primary and secondary sectors (jobs including the creation of raw materials and the processing of them, respectively).
Within the collection of developed nations there are tough laws regulating the use of child labor, this is partly down to UN conventions which suggest legal standards regarding child labor. However the majority of the work done to protect children is done by the governments working within the countries. The earliest laws in the United States concerning child labor began to be enforced in 1918. Similarly laws in the UK began to be introduced at the beginning of the 19th century as a means to protect young children working in factories during the industrial revolution. The "International Labour Organisation" set up the Minimum Age Convention in 1973, which suggested that all developed nations stated a minimum age at which a child could begin employment without a parent's fully informed consent. This age has been allocated at between 14-16 years in all nations which have conformed to the guidelines. All of these laws and conventions have been introduced as a means to protect the welfare and education of a country's youngest members.
We are forgetting of course that there are many nations which have yet to enforce a minimum age for which children can undertake regular employment and that at one time or another all nations have relied upon children as an active part of their workforce. There are then presumably many advantages of child labor, otherwise it would not have been used in the first place. Using this logic there must therefore be many disadvantages which have led to its downfall and abolishment within developed nations.
Child labor's main advantage is that compared with employing an adult it is remarkably cheap. This means that a business expense can be driven down be expanding its child workforce. This in turn increases a business profits, which is the ultimate goal in any economical climate. Child labor can be a key cog in a system which ultimately provides a nation with more money, which in turn grants it greater political power and a higher likelihood of being able to deal with the more advanced, richer nations in the West which tend not to use child labor.
Child labor is a prevalent driving force in countries such as China and Vietnam and it is easy to imagine the scope of goods that are manufactured from such regions. Good which are produced in bulk such as toys, packaging, furniture and clothes are all mainly produced in these countries and others like them, due to the low cost of manufacturing which is a result of child labor. A major benefit means that consumers in developed nations will theoretically pay less for the goods which they purchase.
A final advantage of using child labor is that children often prove very useful in primary and secondary sectors, as outlined in the introduction. Repetitive tasks which require specific skills are easily picked up by children; this is because they are innately designed to learn. Also, in farming communities families often encourage their own children to work as a means of supporting the welfare and the continued existence of the family and the society as a whole. Children are also adapted very well to jobs which adults are physically ill-suited for. There are notorious examples of children doing jobs such as chimney sweeps and working down narrow mine shafts because of their small size.
The first, and most obvious, con involved within child labor is that of the ethical issues involved. Children are correctly depicted as being largely defenceless. Since children have younger, more innocent minds and a smaller physical presence than that of an adult they are much more liable to exploitable by employers. This is why they are so poorly paid for often very hard jobs in poor working conditions, such as those generally present within "sweatshops". Another negative factor of having children working is that they are often prone to physical and mental abuse as a means to force them to work harder or with fewer mistakes. Whilst this drives up the productivity of the children it also damages impressionable minds and ruins a period of a person's life which should otherwise be full of adventure, innocence and discovery.
Child labor can also be interpreted as a vicious cycle. Children are stuck doing poor quality, hard and mundane jobs in relatively unrewarding industries, and because of this they miss the chance to ever acquire a proper education, even at the taken-for-granted level that is provided at kindergartens and primary schools in the developed nations. This impairs even the most basic literary and numeracy skills from developing. In turn this will reduce the amount of workers that can work within the tertiary and quaternary industries. These industries typically deal with providing public services and the use of information technology; these industries are not accessible to nations with generations without proper education.
Having written this article I would, of course, like to point out that I am firmly against child labor and that I am a firm believer in Fair-trade goods and the proper treatment of children within society and their absence from full-time employment.
UN Regulations: http://cyberschoolbus.un.org/briefing/labour/index.htm
Minimum Age Convention: http://en.wikipedia.org/wiki/Minimum_Age_Convention,_1973