I would agree with Kathy D. But I would also point out that a baby breastfed for six months can go to homogenized milk at six months, not formula, if he is also getting a variety of solid foods. And why cannot the mother continue breastfeeding to a year? Or longer, if she could go 6 months full, or 12 months half time? Now what happens to this question if your strictly breastfeeding baby at 6 months refuses formula? It happens often enough. Most formula tastes like a stale belch, at best, and any baby who has been breastfeeding exclusively for 6 months will usually not touch it. A variation on this question is: Which is better, exclusive breastmilk feeding (by bottle or cup) or partial breastfeeding and partial formula feeding. That's a harder one, I think. I would say the younger the baby the more important the exclusivity of breastmilk feeding is. But once the baby is older, breastfeeding, the act of breastfeeding, or the relationship, becomes more and more important, and probably there is some age, when breastfeeding is *more* important than exclusive breastmilk feeding. Jack Newman, MD, FRCPC