"Look for what gets your heart," he said. "Someone who excites you, turns you on. It's a woman who loves being a woman. Who wears her womanhood. Who knows how to flirt and have fun. Smart. Confident. And obviously sexy and saucy and challenging."

Given the problems the last Democratic president had with women you might have thought this was one subject to steer clear of. But Mr Kerry, who has been lambasted by his detractors for being wooden and standoffish, loosened up in an article entitled "A Beer with John Kerry". Asked which actors he found attractive he said: "I think Charlize Theron is pretty extraordinary," before going on to name Catherine Zeta-Jones and Marilyn Monroe.

Mr Kerry also reflected on his time as a divorced senator. "Those were not good days. I think if you ask anyone who's been single on Capitol Hill, you'll find it's no fun. That's not a good world and everyone wants a piece of you, and all I can say is thank God I found Teresa."

He was probably less thankful after he read the comments of his wife, Teresa Heinz Kerry, in an interview in the latest Reader's Digest, in which she said her husband was not "truly qualified" to be president.

"I think nobody is truly qualified to be president of the United States," she said. "I mean, are you qualified to run the world, not run it, but have that influence? No, nobody is."

Ms Heinz Kerry, who told an over-persistent journalist to "shove it" last month, sounded already weary about the prospect of three more months of intensive media attention.

"I'm sure there will be stories that I've given birth to children from Mars," she said. "You know, there are a lot of bored people out there."