No I don't believe they can, but they do say that your baby is more likely to have a food allergy if you eat a lot of foods people are commonly allergic to while you are pregnant. Not sure I really believe that, but some doctors claim that to be true.
So I just googled it and the general consensus seems to be that they are really not sure but they don't think so. They think that babies my have a predisposition to allergys but that it doesn't develop until there is direct contact, and while in utero the plcenta acts as a filter so no "true" food get to baby