Breastfeeding beyond the first year has great benefits for both, Mother and Child. Breatfeeding after this point can provide up to a 1/3 of their calorie, protein, and calcium needs. Continues to be a source of antibodies that fight infections. The longer a Mother breastfeeds, the less risk for ovarian, breast and uterine cancer. It continues to creat a special bond, a source of confort and reassurance after separation. Buitls memories. The average in the WORLD for weaning is 5 years of age. It's natural, there is nothing wrong with it, why would the breast keep producing milk? it is desing to last as long as it is needed. It is up to each one to decide when to stop, accordingly to individual's needs and preferences. I think potty training could come first and then weaning. Children grow up, mature and loose interest in baby things on their own sometimes, then we can guide them to learn grow up things. My son is 21 months old, still breastfeeding and him too has been drink from a cup since he was 6 months old. "Sick and innapropiate" is in the mind of the beholder.