6 years old and still breastfeeding… really???

Why would you continue to breastfeed your child at the age of 6?  Is this normal behavior, or is it perversion?   I am not a psych major, but I think at some point (maybe somewhere around 1 year old) that the child should be weened.  Is it the mom or the child with attachment issues? We all grew up in diferent households with different sets of values.  Chyme in and let me know what you think.