John had always wanted a big family, while Sherlock never wanted a family at all. Their first child was an accident... but John couldn't have been more thrilled. Until, of course, she started to talk. Having one egomaniacal genius in the house is bad enough, but two? Three? Four? The children and Sherlock debate everything from the average rate of decay for the human body to music theory.

Sherlock considers it John's just-desserts that all of their children have IQs over 180.