Well, that's a matter of opinion.
The World Health Organization says:
"Exclusive breastfeeding is recommended up to six months of age, with continued breastfeeding along with appropriate complementary foods up to two years of age or beyond."
The American Academy of Pediatrics says:
_"Breastfeeding should be continued for at least the first year of life and beyond for as long as mutually desired by mother and child....Increased duration of breastfeeding confers significant health and developmental benefits for the child and the mother....There is no upper limit to the duration of breastfeeding and no evidence of psychological or developmental harm from breastfeeding into the third year of life or longer." (AAP 2005) _
The American Academy of Family Physicians says:
_"Breastfeeding beyond the first year offers considerable benefits to both mother and child and should continue as long as mutually desired….If the child is younger than two years of age, the child is at increased risk of illness if weaned." (AAFP 2001) _
Biocultural anthropologist Katherine A. Dettwyler, PhD says:
_"My research concludes that the normal and natural duration of breastfeeding for modern humans falls between two and a half years and seven years. Some children nurse less than between two and a half years years, and some nurse longer than seven years." _