The deep, personal material of the latter half of your life is your children. You can write about your parents when they're gone, but your children are still going to be here, and you're going to want them to come and visit you in the nursing home.
In the quest to understand quantum gravity, we are like children playing on the shore of a vast ocean, occasionally finding a smooth pebble or a pretty shell, while the great ocean of truth lies undiscovered before us.