Robert Fox and Jennifer Holmes may be a New York couple deeply in love -- but even they suspect there's one area they may not have much in common: how often they think about sex.
"Men and women I think are completely different when it comes to sex," Holmes said.
Fox asked, "Don't they say most guys think about sex once every three minutes?"
To put that theory to the test, they allowed Primetime Live cameras to follow them for a day -- and asked them to keep a running tally of those thoughts.
Fox is an advertising executive who works at "Gotham," a trendy New York magazine. It didn't take long for those sexual thought to hit him.
Early in the day, he met a few women in the course of his work, and he had to admit he'd thought about sex already. He told Primetime Live's camera: "Those were some sexy girls, right?"
Sex, in fact, seemed to be all around Fox. Messages came off the magazine covers on the walls of his office. "Sexy, sexy, sexy," he said as he was passing them.
But for Holmes, who also works in advertising, sex didn't seem as prevalent. At 2:30 in the afternoon, she told a Primetime Live camera following her: "I have probably thought about sex not once."
Meanwhile, Fox had moved on to one of New York's hottest department stores, to scout it as a possible party location.
While talking with a female employee, he thought about sex again. When that woman asked if he'd like to see the lingerie department, he had another thought about sex.
Walking past the rows of bras, Fox's thoughts were all sex. When the employee held up a see-through camisole, he thought about sex. When she showed him a sexy shoe, he thought about sex.
"I would say I've thought about sex maybe 50 times today," he said.
Another 90 minutes passed for Holmes, and she admitted, "the thought of sex hasn't really come up."
She admitted that a clerk who helped her while she was shopping was pretty cute.
"He had nice eyes," she told Primetime Live. "But did I think about sex? No, I didn't."
Fox and Holmes reunited later that evening. They compared notes.
"I thought about sex two times all day," Holmes said. Fox said: "Fifteen or 20 times in the morning before 2 p.m., then I thought about it 10 more times."
Before they headed home, they went to a hip fashion party -- where Fox had plenty more sexual thoughts.
The lesson for the day apparently was that men may be from Mars and women from Venus -- but Martians apparently think a lot more often about sex.