According to a commenter (and why should I check?), Kos is claiming the smear didn't originate with him, but with "Alaska Republicans on the radio."

Ah. Yes, that's why we spent the weekend talking about it. Because we were all glued to our radios listening to Alaskan talk radio. We all got this from Rush's cousin, Slush Limbaugh, and his radio show, Slush Limbaugh's Right-Wing Agent Provocateur Gothic Fake Pregnancy Krazy Konspiracy Kavalcade & Professional Toboggan Fantasy League Report.