I guess there are a few things here to consider. I'll just mention two of the ones that I can think of, the first being that of genetics. Though I do not argue the way children are raised influence them greatly, genetics also greatly affect us. Some people just have what seems to be a family history of being socially inactive. Can't change how we are wired!
The other thought I had deals with the economic stability of the family. This definitely has an effect on the upbringing of a child. I feel like this can have many different effects, some being positive or negative.
I agree with the first one but not fully with the second one. Genetics do play a key role like how autistic children have impaired social skills from birth. Having autism at an early age will make it difficult for the child to be socially active regardless of what kind of attachment he/she had.
I don't think economic stability has an effect but rather the problems that comes with economic stability. A child could be raised perfectly happy and normal in a poor family if the parents know what they are doing. Unfortunately poor families tend to have problems like alcohol abuse, depression and etc that could affect the child.
While genetics can play a role if it is something serious like autism, in general, genetics is a factor that should not be considered except in its extreme cases. For example, there have been numerous studies where twins have been separated at birth and raised in completely different environments. The results of the experiments show that the twins had virtually nothing in common, despite sharing the same exact set of genes.
