RAMAZAAN AND CHILDREN
Allaah has blessed the month of Ramazaan with numerous advantages and virtues over other months. This is the month in which the Qur'an was revealed. In one of the odd nights of the last ten days of this month is the Night of Decree, in which worshipping Allaah is better than worshipping Him for a thousand months. When Ramazaan begins, the gates of Paradise are opened, and the gates of Hell are closed. At the end of every night of Ramazaan, Allaah will forgive all the sins of those who really observed fasting in a proper manner, and avoided every act of disobedience.
Children are a important part of your family system. They have rights with regard to education and upbringing, the Messenger of Allaah ﷺsaid: “Each of you is a shepherd and is responsible for his flock. The ruler who is in charge of people is a shepherd and is responsible for them. The man is the shepherd of his household and is responsible for them. The woman is the shepherd of her husband’s house and child and is responsible for them. The slave is the shepherd of his master’s wealth and is responsible for it. Each of you is a shepherd and each of you is responsible for his flock.” Sahih al-Bukhari, 2416; Muslim, 1829 (shepherd here means a ruler, parents etc)
So parents must take care of teaching their children the duties of Islam and other virtues that are recommended in sharee’ah, and worldly matters that they need in order to live a decent life in this world.
Parents must also protect his sons and daughters from everything that may bring them close to the Fire. Allaah says: “O you who believe! Ward off yourselves and your families against a Fire (Hell) whose fuel is men and stones, over which are (appointed) angels stern (and) severe, who disobey not, (from executing) the Commands they receive from Allaah, but do that which they are commanded.” Quran Surah Tahreem 66:6
Allah said: Your wealth and your children are only a trial, whereas Allah! With Him is a great reward (Paradise). Quran Surah Taghabun 64:15
Parents not letting their children to fast, Many parents do not let their children fast during Ramazaan [young children]. This is something counterproductive to a child. By allowing him to fast he will grow up to know he must do this act.
Al-Rubayyi’ bint Mu’awwidh said: On the morning of ‘Ashoora’ the Prophet (peace and blessings of Allaah be upon him) sent word to the villages of the Ansaar saying, “Whoever started out not fasting, let him not eat for the rest of the day, and whoever started the day fasting, let him fast.” She said: We used to fast and make our children fast, [and take them to the mosques] and make toys for them out of wool, then if one of them cried for food we would give him that toy until iftaar. Sahih al-Bukhari, 1960 and Sahih Muslim, 1136
But fasting is not obligatory for young children, until they reach the age of adolescence, because the Prophet (ﷺ) said: “The pens have been lifted from three: from one who has lost his mind until he comes back to his senses, from one who is sleeping until he wakes up, and from a child until he reaches the age of adolescence.”Classed as saheeh by al-Albaani in Saheeh Abi Dawood, 4399 and Sunan an-Nasa'i 3432 
Ibn Qudaamah said:
This means that he should be made to fast and told to do so. And he should be smacked if he does not do it, so as to train him and make him get used to it, just as he should be made to pray and told to do it. Among those who were of the view that a child should be told to fast when he becomes able to do it were ‘Ata’, al-Hasan, Ibn Sireen, al-Zuhri, Qataadah and al-Shaafa’i.
Al-Awzaa’i said: If he is able to fast for three consecutive days without interruption and without becoming weak, then he should be made to fast Ramadaan. Ishaaq said: When (a child) reaches the age of twelve I think that he should be made to fast so that he gets used to it.
The age of ten is more likely, because the Prophet (peace and blessings of Allaah be upon him) enjoined smacking children for not praying at this age, and regarding fasting as being like prayer is better, because they are close to one another, and because they are both physical actions that are pillars of Islam. But fasting is harder, so attention should be paid to when the child becomes able for it, because some may be able to pray who are not yet able to fast.Al-Mughni, 4/412
The father must discipline his child and teach him what he needs to know of religious duties. This teaching is obligatory upon the father and all those in charge of children before the child reaches the age of adolescence. This was stated by al-Shaafa’i and his companions. Al-Shaafa’i and his companions said: This teaching is also obligatory upon the mother, if there is no father, because it is part of the child’s upbringing and they have a share of that and the wages for this teaching may be taken from the child’s own wealth. If the child has no wealth then the one who is obliged to spend on him may spend on his education, because it is one of the things that he needs. And Allaah knows best. Sharh al-Nawawi ‘ala Saheeh Muslim, 8/44 
Shaykh Ibn ‘Uthaymeen said:
A young child should not be forced to fast until he has reached the age of adolescence, but he may be told to fast if he is able to do it, so that he may get used to it and it will be easier for him after he reaches puberty. The Sahaabah (may Allaah be pleased with them) – who are the best of this ummah – used to make their children fast when they were young. Majmoo’ Fataawa al-Shaykh Ibn ‘Uthaymeen, 19/28, 29 
With regard to means of helping children to get used to fasting, that may involve a number of things, such as:
It should be noted that if the child becomes too exhausted, you should not insist that he completes the fast, so that this will not make him hate acts of worship or lead to him lying or make him sick, because he is not yet one of those who are accountable. It is important to pay attention to this and not be harsh with regard to telling the child to fast.
Remember the above point that fasting is not obligatory for young children, until they reach the age of adolescence, because the Prophet (ﷺ) said: “The pens have been lifted from three: from one who has lost his mind until he comes back to his senses, from one who is sleeping until he wakes up, and from a child until he reaches the age of adolescence.”Classed as saheeh by al-Albaani in Saheeh Abi Dawood, 4399 and Sunan an-Nasa'i 3432