What are the advantages and disadvantages of watching TV? Why is watching TV prohibited? Please provide the good reason from which we can convince our children, non-believers and other Muslims.

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

It is a common saying among those interested in the Fatwa that TV is like a sword that can be used for the good and for the bad.
No doubt that there are two kinds of people who are more interested in this issue than others.
First, someone who owns a broadcasting channel and has some control over it, so, he only broadcasts what he thinks is useful and good. Second, someone who owns a TV set and has complete control over it, i.e. he only turns it on when there is a good program (a rarity).
These are the two parties concerned with this debate. Since no one asked about the first type perhaps not a single channel broadcasts only what is good and useful.
As for the second type, they are quite small compared to the vast majority of TV watchers. So, this Fatwa addresses watching TV in general.
The issue can be put in this way: what is the rule of watching TV generally as done by most people. Addressing this behavior the Fatwa is as follows: watching TV has many disadvantages and few advantages.
1) It is time-wasting and leads to neglecting many duties.
2) It portrays the cultures of nations of disbelief as the only model and pattern for us to follow and copy in our lives.
3) It spreads dissoluteness and libertinism through pornographic films, obscene songs and immoral advertisements that show naked or semi-nude women. This leads to viewers becoming to such shameful sins, killing their sense of honour.
4) It assaults the very principles of the Ummah by defaming the faith through films that make fun of the religion and its bearers, or by causing debate about established rules, discussing them and giving opinions about them as if they were subject to being changed.
5) It entices feelings of unsecurity among people through detective films and movies that show youngsters how to steal, kill or rape.
6) Becoming addicted to watching TV spoils the mind and affects the health.
These are among the many dangers of watching TV. There may be some benefits found in watching TV. We mention watching news and useful and good programs. But it is known in the rules of the fundamentals of jurisprudence that avoiding the bad is given priority over getting the good, if one has to do one or the other. This ruling is deduced from the basis that alcohol and gambling were made unlawful though people can get some good from them. Allah Says (interpretation of meaning): {They ask you (O Muhammad (Sallallahu Alaihi wa Sallam)) concerning alcoholic drink and gambling. Say: "In them is a great sin, and (some) benefits for men, …} [2:219].
The Prophet (Sallallahu Alaihi wa Sallam) said: "If I forbid you to do something, then keep away from it. And if I order you to do something, then do of it as much as you can" . [Reported by Imams al-Bukhari and Muslim ].
From the above, we say that the preponderant opinion about this issue is that TV watching is forbidden unless one limits it to what is mentioned in the beginning of this Fatwa, i.e. what is beneficial, good and lawful.
It should be mentioned here, however, that this prohibition is not similar to that of alcohol and gambling since the cause for prohibiting alcohol and gambling is in their own nature, whereas TV watching can be in a good way and then become lawful.
So, if some good people who fear Allah provide some good channels limited to what is lawful, then the rule of watching TV will be lawful. Watching TV will (in this case) be even likable, or even obligatory for some people.
Finally, we would like to invite the leaders of the Muslims as well as the wealthy Muslims to give this matter top priority to educate Muslims through Islamic channels.
Allah knows best.