The book
The Nurture Assumption argue that parenting does not matter in the way children turn out.
But the author makes an exception for parents who seek professional help.
So how big is this loophole?
The National Parenting Survey indicates that 89% of parents used medical professionals as a resource and 82% used resources from teachers and other childcare professionals:
That implies a potentially big loophole, Perhaps 90% of parents are doing stuff that does matter according to the criteria of The Nurture Assumption.
But I am not sure that all this is parenting help since one of the categories was medical professionals perhaps most of that was just medical advice.
The survey does not break out parenting or psychological services. I'd like to see some data on that.
There are lots of conditions where parents seek professional help: Autism. ADHD, Oppositional Defiant Disorder, Conduct Disorder, Learning Disabilities, other behavioral problems. Abusive parents are forced by the courts to get professional training. Foundations and governments support professional parenting training from The Incredible Years program, the Oregon Parent Management Training program, and other parenting programs.
I would guess that at least 10% of parents in the USA get professional help on parenting or behavioral/developmental issues. In some European countries, with national parenting or well-care programs, the rates are probably much higher.
In my own family, I have a total of 9 kids and grandkids (including step-kids). 4 of the 9 have had professional help for Autism, Learning Disabilities, Behavioral Problems, Child Abuse.
It appears that there is a heck of a lot of effective parenting going on out there according to the criteria defined in The Nurture Assumption
What a surprise!