There is more than 1 baby because you are creating an instance even though there is already an instance of both on the layout, which have the Bound to Layout behavior.
You can either, On Start of Layout, BabyGirl/BabyBoy destroy (destroy the instances before trying to create a new one) or place all usable gfx objects on a separate Layout (my preference), that way there is always an instance available to any Layout, but it won't interfere or need destroying at the start.
BTW the gfxfor the babies are ridiculously large. I would scale them down in the Editor.