One highly controversial milestone of physical development is that of toilet training. Toilet training is an example of highly specific muscle control and one of great concern for many parents.

The cultural influences on toilet training have changed over time in the United States. The availability of disposable diapers in industrialized nations has dramatically increased the average age for a child to become fully toilet-trained (day and night, bowels and bladder). Currently, the average age for girls to become fully toilet-trained is 29 months; boys usually take 31 months to become fully toilet-trained. Remember that these are only averages and that these ages may vary for every child. Almost all children are fully toilet-trained by the time they are 36 months old.

Research at least two other cultures and determine their expectations regarding toilet training. At what age are children expected to be trained? What techniques do they use that are different from children in the US? What are some advantages and disadvantages to their techniques?