There has been a lot of research into the long term effects of negative nurturing but we can't forget that everyone is an individual - some remain victims of their circumstance whereas others see their disadvantages as a challenge and excel beyond what they might have achieved if they had no such constraints.
I'm one of the believers that environment is everything in development. Meaning I don't subscribe to the view that people are "born" with talents, only a propensity to develop them. Yes there are genetic advantages in some areas, but these would be reduced if the environment is not optimal. Saving Changes...
"Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in beer."