Can baby with anencephaly grow a brain with stem cells?

No: Brain growth in utero concides with growth of the body and skull and the brain has already spent 9 months growing and responding to stimuli in the womb. A full brain would not grow correclty from stem cells after birth.

Anencephaly: We have difficulty determining the factors which cause differentiation into certain cells. Complex 3-d regrowth is still in the realm of science fiction (which may mean we end up doing it in another 30-40 yrs!).

Can't happen: The issues involved all occur before 28 days into a pregnancy long before most are aware they are pregnant. The process would be like re-wiring a house after it has been completed, but needing to fabricate a skull covering and tissues that are also part of the defect.Stem cells have some promise, but it is unlikely that we would see this kind of major benefit in out lifetime.