Yeah that does sound odd but honestly, how could they forget the baby from just appearing the episode before? They remembered each and everyone of the Borg kids but forgot the baby? That's why I just think, if you really want an answer if would have to be a thinking out of the box one. That's why I came with my idea. Hey, the show is made up anyway. Making up your own ideas surrounding it couldn't hurt. That's how writers are born, right?