I encounter this situation frequently in my office. Many parents have the misconception that all infants will be ready for foods between 4 and 6 months of age. The truth is that very few infants are developmentally ready at 4 months. In addition, it is now recommended to delay foods until 6 months in order to decrease the chance of allergies. I also have found that some infants are not developmentally ready for solids until 8 or 9 months. You can click here to read about what signs to watch for to determine when your infant is ready for foods. Breast milk is nutritionally complete for at least the first year of life. This means that infants can go for at least a year on breast milk alone, without eating any foods, and be nutritionally complete. Offering foods between 6 and 12 months of age is simply for social development and to get infants used to eating.
I encourage parents not to try to coax their 6 month old into accepting solids before he shows many of the signs of being ready. This can create a picky eater and negative feelings about eating.