With objectivity, Asperger's Syndrome is a genetic condition that occurs in utero &/or soon after - we are genetically programmed.
But I do believe that we are subject to our upbringing and how we're treated. Certainly, there are Aspies who are, and were always, loved. For instance, on our own Wrong Planet Parent's Forum, we have some awesome parents whose kids are on the spectrum - they're well adjusted and treated well. There are some really well-adjusted Aspies from supportive families who thrive with their diagnosis.
Instead, I think the question is how does bad upbringing affect AS? Well, it makes it much harder and more complicated. From what I've learned from the Wrong Planet, no one suffers from Autism/AS. Instead, we suffer from how we are perceived, and mis-perceived, by others. We suffer from the consequential mistreatment. We suffer from being excluded. From being bullied and teased. Aspie kids are prone to bullies and struggle due to our sensitivities. I've had problems with trauma, diagnosed, because I was cruelly abused by a neuropsych professional. I suffer from being shy and not speaking.
So, instead I think we suffer from the effects of being mistreated as it uniquely manifests in us as Aspies. Bad parenting does not 'cause' Asperger's, certainly! Instead, it exacerbates symptoms that are latent.
_________________
The ones who say “You can’t” and “You won’t” are probably the ones scared that you will. - Unknown