At the Republican convention, Sarah Palin introduced herself to the world in the speech of a lifetime.  Her family was nearby and joining them was Levi Johnston, the father of the baby that Palin's 17-year-old daughter, Bristol, is carrying.   Sarah Palin is often compared to Dan Quayle, George H.W. Bush's surprise 1988 running mate, who the media often suggested was unqualified for the Vice-Presidency.  Polls show that as many as a third of Americans believe Palin is unqualified as well.  Yet the Quayle associations don't end there.  In one of his most famous speeches, Quayle criticized the television character Murphy Brown for having a child out of wedlock.  Quayle's speech was criticized by the media but hailed by conservatives for pointing out that a role model like Brown having a child out of wedlock could send the wrong example to young Americans.   The media is not sure what to do with Palin's daughter.  Palin's daughter is pregnant with the child due around New Years.  The Palins and Levi Johnston's parents have both stated that their children plan to wed sometime before the baby is due.  When you are a lifetime member of the NRA who hunts grizzly bears, a shotgun wedding is not just a metaphor.  You think your life is busy?  This fall, Sarah Palin will be running for vice president, serving as Governor of the State of Alaska, caring for several children, including a four month old, sending a child off to fight in Iraq........and planning her daughter's wedding.   Much as Quayle criticized Brown for her pregnancy, many conservatives and liberals are now worried about teen pregnancy in America, and for good reason.  After a decade of declining teen birth rates, in 2005-2007, teen pregnancy numbers began to flatten out and have begun to show signs of increasing.  This is worrying social scientists, some of whom blame the increase in out-of-wedlock births on celebrity pregnancies, including 17-year-old Jamie Lynn Spears, Britney Spears' sister.  Now there is another prominent 17-year-old who is with child.  Only this time, conservatives are running to her defense.  While Bristol Palin and Levi Johnston certainly deserve to work through this with some privacy, Levi's attendance with the Palin family at the convention is thrusting this issue into the public eye.  Will a conversation about roll models, teen pregnancy rates and family formation follow?  We'll see.  What would Dan Quayle say about all this?