Barack Obama issued an appropriate statement:

I have heard some of the news on this and so let me be as clear as possible. I have said before and I will repeat again, I think people’s families are off limits, and people’s children are especially off limits. This shouldn’t be part of our politics, it has no relevance to governor Palin’s performance as a governor or her potential performance as a vice president. And so I would strongly urge people to back off these kinds of stories. You know my mother had me when she was 18. And how family deals with issues and teenage children that shouldn’t be the topic of our politics and I hope that anybody who is supporting me understands that is off limits.