Christine is a 41 year-old New Yorker. She has competed in 11 marathons, runs her own consulting firm and is working on her Ph.D. She is also single. Christine recalls, "I recently had a male friend tell me, 'Chris, men just want a woman who's going to be home and be a great wife and mother. You're too intense. Look at you, you're going 100 mph all the time, no guy wants that.'"

"I am attractive, in gosh-darn good shape, fun, great sense of humor, full of energy and life, smart and ambitious," says Christine. "You would think these are qualities men would like—and most [men] say they do—but sooner or later, I feel like they begin feeling inferior or inadequate as a man or breadwinner." Christine isn't alone in her frustration. According to the book Why Smart Men Marry Smart Women, over half of single women believe that their success is intimidating to men.

So, do women really intimidate men? We asked men what they thought and were surprised by their answers.

"Strong, aggressive, ambitious people intimidate weak, passive, lackadaisical people regardless of sex. They remind these people of the existential crisis that cause their current state of being," says Daniel, 25, a Web editor from Boston. "It's the gap in intelligence—not gender—that causes the intimidation."

Jeff Kamp, 30, a software engineer, agrees, "The intimidated male might not be intimidated by the woman, but by the power, ambition and aggressiveness, and his reaction may cause a woman to see it as her being a woman."

A few men even admitted that they thought women cried intimidation as a cop out. "Do strong career minded women intimidate guys? I doubt it," says Joe Woods a 25 year-old a hardware engineer living in Iowa. "It probably has more to do with these women having chosen to spend their time and effort trying to accomplish other goals instead of pursuing and working on relationships."

"It's totally an excuse," says Clouds. "Men use it when they can't meet women too."

Scott White, 29, is a fitness instructor and doesn't even consider the possibility of intimidation. "No way no how," says White, adding, "although, I am not intimidated by much, especially not women. I know this answer sounds a bit crude maybe or chauvinistic…why would I ever be intimidated by a woman?"

Recent research supports these conclusions. According to the 2005 Current Population Survey, a single 30-year-old woman is more likely to marry by age 40 if she has a graduate degree than if she doesn't. But Jane Scandurra, producer and director of the documentary Single warns against reading too much into these statistics. "Either biologically or sociologically men have it ingrained in their minds that it is a competition," says Scandurra. "There may be some guys out there who aren't intimidated, but are there enough?"

"Of course men deny it," laughed Marilyn Barnicke Belleghem a family therapist. "they just aren't telling the truth because the question intimidates them."