Let me clarify my position on the nature VS nurture debate.
Both are absolutely critical, no doubt. On the genetics/nature side, you must be born with the proper equipment to have sound reason. A person with an extra chromosome such as down-syndrome carries a genetic defect that directly affects their mind/brain. Not to mention there is some plausible correlation to inherited intelligence, from your parents of course. +1 for nature.
On the nurture side, let me just tell you a story. The details in my memory are fuzzy, but the gist of it is still intact. I read an article about a rural family back in the 1930's that had an "illegitimate" child so to speak. Long story short, the grandparents took custody of her and locked the poor child by chains in a dungeon/cellar for the first 16 years of her life. The never talked to her, they never had physical contact with her, they never bathed her. They fed her pig slop, never cleaned the shit and piss out of her "cell", and basically demonstrated in my opinion the biggest act of cruelty that I have ever heard of.
The authorities found out, rescued the 16 year old girl, and threw the grandparents in prison. She went to a psychiatric facility and shrinks tried their best to help her. Despite their best efforts, she could not learn to speak, communicate, or act in any way that was considered both human and civilized. She was, by all intensive purposes, a brainless animal. Her mind had never received the proper stimulus necessary to develop. It makes me tear just typing about it.
So, it's +1 for nurture. Both nature and nurture are absolutely critical for becoming what we are now.