Hamish And The baby Boom! by Danny Wallace

Hamish and the PDF have been left in charge of Starkley while his dad and the rest of the Belasko agents are off hunting down the universe's second-most dangerous villain - Axel Scarmarsh!
But nothing bad will happen while he's gone, right? WRONG!

Suddenly the babies of Starkley are on the rampage and causing chaos - but only  Hamish and his friends seem to be worried about the odd behaviour. 

What’s behind the baby uprising and can the mini mutiny be stopped before EVERY BABY ON EARTH rises up?!