I ran across an article the other day in Scientific American Mind by Robert Epstein, a longtime researcher and professor of psychology, which summarized a research study on what parenting practices produce better results than others - that is, practices that produce better relationships between parent and child and happier, healthier, and better functioning children.
The studies also sought to answer "why, in fact, do most parents continue to parent pretty much the way their own parents did - or, if they disliked the way they were raised, the exact opposite way?"