To be fair to any other chat show, the odds are that they'd probably ask this question if they thought they could get away with it.
That's half the charm of 'The Tommy Tiernan Show' - that they're able to get away with asking just about any question, and the interviewee knows that it's coming from an honest standpoint. Even asking Bob Geldof of the Boomtown Rats what sex is like at 68 might seem like an eyebrow-raising question, Tiernan quickly follows it up with an honest answer.
"My curiosity is I'm 50, I want to know what sex is like when you're 68," Tiernan explains, with a bristle of laughter from the audience. Sure, it's a ballsy question, but it's done in a spirit of trying to understand rather than necessarily entertain. It's almost as if the laugh was a bonus, and he actually wanted to know.
Naturally, Geldof gives a thoughtful answer to a thoughtful question, opening with the obvious answer that it's not without it's difficulties. "That laser-driven drive of a sixteen-year-old clearly isn't there and it tempers, which you must understand at 50."
It's a fascinating answer, and what a show yet again. Take a look.