To that end, the Feels will come to those witnessing or living through a particularly moving moment when their heart is fullest and add additional emotion until the heart can no longer contain the pressure.
Most parents start the training when their children are between two years and three years old. But there's no official age, and you needn't potty train your toddler at all if you don't want to.
At the age of 18 months, children become fascinated by the behavior of other children their own age or older. This is why often the 2nd and 3rd child is potty trained a lot earlier than the first child. By the age of 24-30 months, they start to understand gender differences and focus on imitating the behavior of the same sex parent.