People know a cheap shot when they hear it.
When it is at the children of opponents, it may bite you back.
That debate and comment lost Kerry a permanent 1-2 points IMO!
If sKerry had used Ms. Cheney's sexual preference to make a point, It might have been understandable.
The fact is, after mentioning she was a lesbian, he want mumbling on and never answered the original question, nor made any real point.
That justifies claims that it was a planned backstabber (but it backfired).
That they do. He could have been talking about their child. Kerry's gamble was ill conceived and it has been ill received.