I have a question regarding my 13-month-old son. He will not drink any kind of regular milk. Should I keep giving him formula (he's on Carnation Follow-up Soy, powdered) or stop using the formula and "wait" for him to develop a taste for regular milk? Is there some other type of powdered milk that would be okay to try? How can I make sure he's getting enough calcium?
There is no reason why you can't continue to give him the Carnation unless its expense is a problem for you. I don't know your child's history, but I'm assuming that since he's on soy formula, he probably had some difficulties with the traditional milk-based formula when he was younger. Most children who have a milk intolerance can eventually take whole milk, but the timing is hard to predict.
It would be reasonable to try again every few weeks or so. There should be calcium in the soy formula, so you shouldn't have to worry about him getting enough. You could also try giving him other milk products, such as cheese, yogurt, or ice cream. If he tolerates these, then there's no physical reason why he can't take milk, and the resistance is then more likely due to differences in taste.
If this is the case, you could try mixing a little milk into his formula, gradually going from mostly formula to mostly milk over a week or two, so that he gets used to the new taste. You should not use skim milk or low fat milk for babies this age.