Although Sigmund Freud didn't bill himself as a parenting expert, he sure had plenty to say about potty training. Just as breastfeeding is the behavioral marker of the oral phase, toilet training is the attendant milestone of a child's anal phase, which lasts from 18 months to 3 or 4 years old. Freud suggested that forcing a child to abandon diapers before entering the anal phase could be detrimental to his or her development, sowing psychological seeds of hostility, not to mention bed-wetting [source: Dewar]. Freud's daughter Anna, who followed in his psychoanalytic footsteps, linked children's gradual control of their bowels, preferably at about 2 years of age, to their internal power to control aggression [source: Erwin]. To enable those external and internal processes, father and daughter Freud proposed that parents should permit toddlers to dictate their own pace of potty training.
Contemporary research on potty training has debunked Freud's bathroom concerns and linked soggy sheets to biological issues, but his warnings make sense, considering what parenting experts in the early 20th century advocated. Guidelines at the time outlined strict potty training regimens, complete with verbal and physical punishments if little ones refused to go, which most certainly would've resulted in a torrent of psychological repression and hang-ups [source: Dewar]. No wonder Freud fretted so much over fecal matters.