I have found so many critics of extended breastfeeding are complete ethnocentric boobs (pun intended)…
I just find it frustrating that people really are uneducated on the natural time-frame a human naturally weans. I hope by using my personal experience as a child breastfeeding until the age of six, and my experience breastfeeding my own children, will help people realize that it is quite natural and is not needed to be judged negatively.
The lovely Dr. Katherine Dettwyler is a professor of Anthropology at the University of Delaware, and is affiliated with Texas A&M University (where she taught from 1987-2000). She is has kindly allowed me to post some of her work on extended breastfeeding. She has breastfed two children over the age of four years, they both are proud of it, and they tell people themselves.
Here is the link to her page.