Someone once said “We are all born the same and our differences are cultural differences.” I think this is probably the closest statement to the truth to describe our differences I have seen, but even this falls short on the litmus test.
If it were completely true, two people growing up in the same household, attending the same schools, and having the same experiences growing up would think exactly the same on social and cultural topics. However, there are still those who differ from each other.
I have seen two children of a welfare parent take totally different paths as adults. One strove to become a better person, worked hard in school and went on to college on scholarships and work to became a professional while the other grew up to be the next generation of a social parasite.
I have seen two siblings from a middle class family grow up with one becoming a staunch liberal and the other very conservative. The liberal worked hard to earn the most money he could while the conservative worked hard serving the country and was happy as long he met his basic needs of food, shelter, and clothing.
So the cultural aspect may have an influence, but it definitely is not the final line. Thinking about this, I would say:
There is no cookie cutter to humanity. We are all born the same but each develops uniquely based upon his/her own will. ~ ME