Okay... Completely off-the-wall thought: Babies (not a freaking clue why I went there either)
For the new parent users, can you add something that does (something like) month anniversaries for the newly born? Seems like they measure time in month for the first year or so for the little ones (e.g. how many months is he/she/it...).
So anybody under 2 years old (that seems like the usual cut-off) gets a monthly entry for being X months old.