What research. And what is the definition of best? Generally speaking eons of evolution has shaped "what comes naturally" to be the parenting traits most effec

What research. And what is the definition of best? Generally speaking eons of evolution has shaped "what comes naturally" to be the parenting traits most effective at enabling survival of the fittest or some other trait that enables mass propagation of genes. But survival of the fittest is just one possible definition of "best".