This is a common question amongst patients. It really depends on the specific case. Most frequently, the answer is yes, a baby with polysplenia will develop immunity within the same timeframe as any "normal" child (not that there is a normal in human development). In rare cases, however the division of the spleen can be so detrimental to the child's immuno-development, that it can pose a serious health concern. If this is the case, then the baby will have a low survival chance, and seeing as you can't spell the disease your own child has, maybe you shouldn't be reproducing in the first place. My diagnosis: suicide pact - you and the kid.-Barry Marshall, D.D.S.