Do singles have better sex lives? Are women born to be married and monogamous? 20/20 takes a look at dating, mating and our sexual side -- and 10 things our mothers never taught us in "Sex: Myths, Lies and Straight Talk."
20/20 put the following popular notions about romance and sex to the test and found some surprising answers.
Ask any woman: Men who are 5-foot-9 -- that's average -- or taller clearly have it over their more compact cousins.
And it turns out a man's height has always helped him get to first base. Nearly 10 years ago, 20/20 concocted a test to illustrate an indisputable rule of love: height matters.
20/20 recruited men tall and short and put them in lineups behind a two-way mirror, then invited groups of women to look at the lineup and choose a date. The women were told various positive things about the shorter men -- the men were described as having interesting careers, impressive educational pedigrees or a lot of money. The women always chose the tall men.
Nothing succeeded in making them prefer the shorter men. One woman even suggested that 20/20 describe the tall men as "murderers" to even the odds for the shorter men in the test.
Professor Allen Mazur of Syracuse University, who at 5-foot-7 stands a few inches below average himself, did a study that found taller men are likely to marry more often and have more children. Mazur said one possible reason for his finding is that "taller men, by virtue of being more attractive to women, perhaps have more opportunities with women other than their wives, which leads to a breakup of marriage, which leads to a remarriage to a younger woman, which leads to another child."
Would it be fair to say from the study that it seems that taller men were hot and the shorter men were not? "That would be an inference. You could also infer that the shorter men are better husbands, and they have more long-lasting marriages," Mazur said.
From Mae West to Marilyn Monroe to Farrah Fawcett to Pamela Lee Anderson, blondes have embodied the notion of the sex symbol. But it was a Clairol hair color advertisement that raised the big question: Do blondes really have more fun?
Do they? 20/20 hired two actors to go platinum to find out, and came up with a very unscientific test using hidden cameras.
Actress Diedre Lorenz found lots of people willing to help a fair-haired maiden in distress. Some went beyond the call of duty, offering their phone numbers and to take her out for a drink.
Lorenz said she doesn't typically get the sort of attention that she received with her blond tresses.
What about a platinum-haired man? Actor Jake Mayers gave it a shot and said he felt "sexier, and I do feel more attractive."
While surveys say blondes are often perceived as "ditzy" but "glamorous," brunettes are seen as "competent" and "trustworthy."
Posing as a dark-haired tourist, Jake felt he got less action but more respect.
As a brunette, Deirdre felt invisible. She got dramatically less attention than she did with her blond hair.
"Men basically were throwing their phone numbers, begging me for my phone number, wanted to take me out sightseeing, take me for drinks," she said. "Today, not an offer. Literally, I did not have an offer."
If it's any consolation, studies show women are nicer to brunettes.