Heather Turgeon, in Babble, writes a note of skepticism about the "natural" mode of parenting: "The Science of Cavemom Parenting — and Whether You Should Try It".
This isn’t to say that I dismiss the “natural” way — far from it. Actually, I’m a mom who has opted for many of these ways myself: I adore the sling, I had a drug-free birth, and I’m breastfeeding my 18-month-old. I certainly support any choice that works for an individual family. But the idea that these practices or any other are superior because they’re how we’re “supposed” to do it is misleading. And it’s often used with backward logic to support a point of view or philosophy that people already have. As [Paleofantasy author Marlene] Zuk writes, “We have a regrettable tendency to see what we want to see and rationalize what we already want to do.”
If evolution teaches us anything, it's that human children in the past had to develop in a wide range of circumstances. In terms of emotional trauma, loss of caregivers, survival as orphans, extreme hunger, long recuperations from severe injuries, children in the past faced incredible challenges -- challenges that are still met and overcome by many children in the world today. Besides that, social groups in the past had incredibly different expectations and attitudes about childrearing, just as different societies do now. The genes in today's children had to survive all these varied circumstances. If there's one thing our children are adapted to, it is to survive the unexpected.
So it is nonsense to think that there is an "ideal form of parenting" to which children today have been genetically fine-tuned by their evolutionary history. The range of plasticity of outcomes is so wide that there is no sense trying to optimize beyond a certain point -- indeed, additional effort spent trying to be the "perfect parent" is probably going to subtract from the basic ability to be a good parent. What works well for one child may be very bad for another, because kids are variable.
That's the lesson of evolution: we should tolerate variability.