I personally don't see a need to breast feed a boy or a girl any longer than a year. A lot of people do it though. The pediatricians have said that after a year there is no longer any nutritional need to breastfeed. The same for formula. Babies only need those nutrients for the first year. Both of my kids were drinking whole milk before a year. Also as soon as they were able to sit up I started them on a sippy cup. They were both off the bottle by about 10 months old. This is just my opinion but I think when a mother breast feeds her child longer than she has to it's because she is having a hard time letting go.