I would be fine if they would keep family matters to themselves. But when they crassly bring up Mary Cheney's lesbianism for political points, they open their own lives to scrutiny, because the issue has then become character.
And as the article points out, Ms. Edwards' silence here is uncharacteristic, especially considering she could do everyone, particularly her own kids, a lot of good by airing the issues of artificial insemination.
Of course, if they tossed fertilized eggs, they have reason to fear the airing of this issue.
The paramount issue IMHO is two children, age three and six, who should find out from their parents, not taunting schoolmates, about the question raised in this article. At an age that their parents decide is appropriate. Which is certainly not six years old.
I cannot believe how low Slate has sunk. OTOH, maybe I can. No matter how you feel about John and Elizabeth Edwards, this is totally out of bounds.