As Ace notes, Saletan bent over backward to keep Chelsea Clinton off of the list; but Ace also notes that he probably had to, in order to get the basic argument published. So be it.
Saletan, walking through recent single daughters-of-candidates-and-Presidents/VPs, their surprising lack of pregnancies, and the reason why it's surprising, finishes up with the rather harsh conclusion:
If any of these daughters conceived, but no pregnancy or birth was reported, what happened? One possibility is miscarriage. But the Guttmacher analysis suggests a different answer: Most unintended pregnancies in the higher income and education brackets end in abortion.
Remember that before you judge or poke fun at Sarah Palin. She's not the candidate whose daughter messed up. She's the candidate who didn't get rid of the mess.
Bolding mine: we seem to be having an influx of people not willing to take the point.