Bigger isn’t always better. Size doesn’t matter. It’s all about how you use it. You think you’ve heard it all, but is all that stuff just out there to make guys feel good about what they've got?

We decided to take a look at what science has to say on the subject of penis size. (Read more about man's best friend in 10 Things You Don't Know About Penises.)

Penis Size by the Numbers

There are a number of studies on penis size ... unfortunately, the results don't lead us to a cut-and-dried conclusion.
  • According to statistics taken by the Alfred C. Kinsey Institute for Sex Research, the majority of white college men have an average penis length of six inches. Unfortunately, that's hardly a representative study of all men.
  • According to Hunter Wessells at the Journal of Urology, who measured the flaccid and erect lengths of 80 "physically normal" men, the mean flaccid length is 3.5 inches, while the mean erect length is 5 inches.
  • Probably the most famous study of penis size comes from a study in the journal Personality and Individual Differences by Richard Lynn, emeritus professor of psychology at Ulster University. It found that there's quite a range of penis sizes worldwide. The United States came in at 5 inches, with the Congo coming out at the top of the list with an average of 7.1 inches, followed closely by Ecuador, Ghana and Colombia. The study ostensibly collects data from 113 countries, but has taken some flak from academics, who suggest that the data has "no methodology." Ouch.
  • The Kinsey Institute has measured the largest erect penis at 13 inches, and the smallest at 1 3/4 inches.

What Men Think

Perhaps what's more important than what's normal is what men think is normal, or how they feel about what they have. And, if all the Internet ads for penis enlargement are any indication, there are a lot of dissatisfied guys out there. A study conducted in 2006 showed that nearly half of the men in heterosexual couples wanted a bigger bone. In addition, men who had larger penises rated themselves as better looking.

Of course, based on these studies, it's no surprise that penis size factors into to men's body image, as shown by a 2008 study. It looked at what affected a man’s perception of his own body in online questionnaires given to 200 heterosexual men. Penis size was something that many men were worried about or dissatisfied with, in addition to weight, muscularity and height. Clearly, many men see size as an issue - and not just when it comes to their penis. The question, however, might who it's really a problem for.

What Women Want

Men may fall squarely on the side of bigger is better, but research shows that most women have a much more varied perspective. One U.K. study analyzed the findings of multiple international studies on penis size. One of the key findings was that 85 percent of women were satisfied with their partner’s size, while only 55 percent of men reported being satisfied with it themselves. In addition, 90 percent of women said they preferred a wide penis to a long one. They also said that the size of a man’s penis did not factor heavily into how attractive they found him to be.

Although it seems that men favor size more than women need it, science ultimately has differing opinions on whether or not size makes a big difference within the context of actual sexual intercourse. In a study conducted by Stuart Brody, a sex researcher in Scotland, 323 women were asked to review their past sexual encounters and rate how important size was. They supplemented this with the additional question about whether or not they were able to have vaginal orgasms. Of these women, 160 experienced vaginal orgasms, and 33.8 percent of that group said that they preferred longer-than-average penises. That's a significant percentage, but it's hardly a deal breaker. Based on the study, Brody concluded that it was more likely for women who experienced vaginal orgasms to prefer longer penises.

Another factor to take into account is that the female vaginal canal is about 3 inches long when a woman's not aroused, and no more than about 5 inches long when she is. So, it seems that the very lowest average recorded size of the male erect penis (5 inches) should be more than sufficient, especially considering that most nerve endings are found in the first third of the vagina. (Learn more about this lady part in 10 Things You Don't Know About Vaginas.)

Is Bigger Really Better?

In the end, the answer to the question of size may be same as a lot of questions that have to do with sex: The answer's personal. Based on the research, it seems that size may matter on the ends of the size spectrum, but most guys in the middle are quite alright. Plus, the large percentage of women who say they're happy with what their man's got suggests that maybe there's a perfect size for everyone. As long as both partners are having fun, who's measuring? (Of course, erectile dysfunction's another story. Read more about that in The Flaccid Truth About Erectile Dysfunction.)