Pediatricians now say early potty training is not that good, especially for boys. Early potty training tends to lead to bed wetting for boys. I think it depends on the child when they want to. Both of mine were 3 when fully trained. My grandsons were 3 and 3 1/2. They do learn to potty on their own when shown how and why. I know daycares had to change their rule that a child had to be potty trained before age 3.