Two studies published in the October 1 edition of the New England Journal of Medicine set out to answer that very question.
In both studies, babies with one or more relatives with celiac disease were watched to see if the timing of the introduction of gluten in their diet had any impact on whether or not they developed the disease.
In one study, babies were either randomly assigned to begin gluten at age 6 or 12 months. In the other, babies were randomly assigned to begin gluten or a look-alike substance that was gluten-free at age 6 months. Neither study showed that timing of gluten introduction impacts the development of celiac disease. Furthermore, neither the number of relatives with celiac disease nor breastfeeding or formula feeding had any bearing on which children developed the disease. So for now, there is no reason to delay introduction of gluten in hopes of preventing celiac disease.