I will say very important in a good number of ways which i will talk on in the following points..
1. Financial security
As a child, you need financial support to cater for your needs since you are not responsible for yourself at that age and what better soirce of financial support can you have if not from family. With a family by your side you are confident that you will have a source of financial provision and that will go a long to help children grow normally without having to become adults overnight to fend for themselves thus limiting them from having a normal childhood experience that has a role to play in their normal growth.
2. Love and a positve psychology development
Children that have grown up in a family that loves them and shows them that they are loved have in most cases turned out grow healthily and positively in terms of psychology. On the otherhand children who have grown up without family have shown a negative psychological development and most at times have demonstrated a slow rate in their growth.
3. Morality
Children who have been brought up in a family environment have been impacted with moral values that teaches them of how to lead healthy and successful lives. They have also been under family discipline measures that guides them on how to live responsibly introducing them into thinking as adults and behaving well. This has helped in the growth of their personality and a better expression of it while children that have grown out of the family context have been studied to show no growth and development in healthy lifestyle and responsibility.
The conclusion of the whole matter is most children that are nurtured in the family have experienced positive growth and development in behaviour, character, responsibility, skill etc.
Family plays a great role in not only just growth but healthy growth in children and in ensuring that they exhibit their full potential..
Hope this helps...