To be fair, the strong/weak distinction only makes sense from a religious perspective in the first place. The statements of belief, you see, are applicable to each and every god, individually (assuming that there is only one god, who happens to be yours, is cheating). Oddly enough, the people most likely to "believe there is no Thor" are those who believe that there is a Yahweh, and vice versa (no, not those two in particular--substitute any religious belief that denies the "truth" of other beliefs). So, Pat Robertson is a Strong AThorist, a Strong ARaist, a Strong APoseidonist, a Strong AFlyingSpaghettiMonsterist... I do not like the "strong" and "weak" labels, precisely because they are phrased in the terms of believers.
A baby does not have any discernable belief in any particular deity. We do not, however, say "ooh, look at the cute atheist baby!"; because it is the default, no label is needed. Eventually, we may have a Mormon child, a Baptist child, a Shinto child, a Greek Pantheist child, a .... But right now, if the baby is born to X religion, he or she may be adopted into Y or Z religion, and they don't even have to check for blood type or Rh-factor or anything... Right now, it's a baby. Period.