The Tao of D&D: Parental Abandonment is an article that deals with the family of the RPGer. In a nutshell, Adventure starts with the end of the family. However, the powerful fantasy that a child choses to leave his family to seek his fortune is very powerful. Also, what if the father kicked his son out?
Suppose the son is living in a Polygamous Family environment. He comes of age, and his culture fears unmarried young men with their women. So they urge the father to kick the boy out of the community to find a wife that is acceptable to the community (that is, she accepts plural marriage as the norm and even beneficial). Effectively divorced from his family, the young son goes into the world to find his fortune and to build his -- well in an ideal plural marriage environment you can't call it a harem. It's plural marriage.
So, an outcast, he is forced to go out in the world and go on adventure to build a family. When he returns to his father who has more than one wife the father explains why he had to kick him out. It seems that a single young man is a danger to the polygamous community. Young girls in the community never choose a single young man in that instance. They'd rather become a sister wife to an established good man. So, a young man must become established with a wife out in the world.
Other impeteus for adventure, without the parents having expired:
* A young man may feel that he's outgrown his family and he has to leave to grow and gain more experience. He leaves his ma and pa to find his fortune out on his own.
* War is called, and a young man is impressed into service to help his countrymen defeat their enemies.
* A young man is called by God or a god (depending on your mythological setup) to go on a religious journey. This is good for coming of age.
* The black sheep in the family is absorbed into the local thieves' guild and becomes a level 1 thief (in "modern" D&D, this class is called the Rogue).
* Some cultures may have children born under an auspicious sign to be trained in a particular guild. For example: the Elder Scrolls world, Argonian children born (hatched) under the Shadow are called Shadowscales and are immediately given to the Dark Brotherhood for training. They are to serve the dark god of Chaos, Sithis. They are ripped from their old family and given to a new family.
* Other impetii for adventure can be that the adventurer is kidnapped at a young age.
* His real father is a powerful duke, and he or she must adventure to make his or her claim.
* Or worse yet, his family is under a curse, and the adventurer must find a way to make things aright.
It's clichéd to start with a dead father or a dead mother. Or to be orphaned. These stories and backgrounds have been done TO DEATH. That is why its a cliché. Some clichés are not meant to be followed. There are devious ways for a character's family to be alive and to have adventures with a PC without resorting to having one or more suffer an unfortunate end.