In pre-islamic arab, it was a pagan ritual to kill the baby girls. Pagan Arabs used to bury their daughters alive and they used to feel so much shame if a girl was born in their home. In Indian subcontinent, this ritual still prevails. In fact, with the advancement of technology, if the gender of child is identified as female in her mother's womb, mother either chooses to abort herself or she is forced to drop the child because in paganism, girls are not liked and they are considered a burden.
Anyway, when Islam lightened up Arabia, killing of daughters was strictly prohibited and such an act was loathed.
Children have many rights in Islam, not just one or two, they are listed below in order of their importance.
1: Bringing up
the first and foremost rights children have in islam, is their bringing up. Islam is very strict about it. Children are a huge responsibility and not just a toy with which one can play and then throw away. Children should be brought up in a proper islamic life style where they could learn being a good Muslim. If they are not brought up in accordance with islam then parents would be sharing their burden of sins along with all the sins their children committed because of their negligence in their parental duty. It is mentioned in a sahih hadith as below;
Allah’s Apostle , Sallalahu Alaihi wa Sallam, also Said: “ Every one of you ( people) is a shepherd . And every one is responsible for whatever falls under his responsibility . A man is like a shepherd of his own family , and he is responsible for them” This Hadith is reported by both Bukhari and Muslim.
If children are good muslims as are their children then they all will join each other in jannah, as promised by ALLAH swt Himself.
“ And those who believe and whose families follow them in faith , to them shall We join their families : Nor shall We deprive them ( of the fruit) of aught of their works : (Yet) is each individual in pledge for his deeds.” 25:21
2: basic necessities
Not only their bringing up but also their clothing and feeding is a responsibility that lies to parents. As already said, children are not a toy to play with, but there are a huge responsibility. They cannot live on their own, nor can they survive. They also need advice in all walks of life. They should not be left unfed, or underfed. Nor should they be clothed like beggars. A sad reality of today's world is that people kill their own children because of the excuse that they cannot feed them. In west, a mom was recently reported convicted of killing her son of hunger. She did not feed him for five days and he died at the age of five. This kind of attitude is highly disliked in Islam. Those parents who do not care for their children, they will be asked on the day of judgement about this very strictly.
As discussed earlier, children should be treated equally, they should not be treated unjustly. Both girls and boys are gift from ALLAH swt. Children ensure linage and family continuation. As for treating them equally, there is a hadith which explains it very well.
It is narrated by Abubaker , Radhi Allahu Anhu , who said that Allah’s Apostle , Sallalahu Alaihi wa Sallam, was informed by one of his companions , al-N’uman bin Basheer , who said:” O prophet of Allah ! I have granted a servant to one of my children ( asking him to testify for that gift) ,” But Allah’s Apostle , Sallalahu Alaihi wa Sallam, asked him :” Did you grant the same to each and every child of yours ?” When Allah’s Apostle ,Sallalahu Alaihi wa Sallam was informed negatively about that , he said” Fear Allah , the Almighty, and be fair and just to all of your children . Seek the testimony of another person , other than me. I will not testify to an act of injustice.” This Hadith is reported by both Bukhari and Muslim .
Thus, children should be treated with respect , with love and with equality. Our beloved prophet Muhammad pbuh is an excellent example in this regard.