How many brothers/sisters Ducky, Spike and petrie actually have?
The number of brothers/sisters that Ducky, Spike, Petrie and even cera have, changed very often...
I mean, in LTB1 they all were born with brothers and sisters: Cera got 3, Ducky got 3 and Petrie got 5. Spike is Ducky's brother, so he've the same brothers and sisters as she has.
And in LTB2, their parents got new babies. Why not.
But in the following sequels the number of their brothers and sisters isn't always the same.
Of course, it doesn't matter, but actually it seems a bit strange.