For two  1) When the writer stoops to cover his own family, you can bet he's stuck for ideas; 2) Unless one's family is terribly unusual, such efforts violate a great unspoken but true  Other Peoples' Kids Are Boring.
You know a writer is running out of ideas when he decides to write about his own family; unless his family is really unique, it violates an unspoken rule about how other people's kid are boring.
Most of the time, writing about one's family is a good idea even if nothing special is going on with them.