For starters we need a good understanding of how the penis is constructed, and how it works. The penis is composed of three chambers; the two cavernous bodies (or corpora cavernosa) which lie side by side on the top of the penis, and the spongy body (or corpus spongiosum) which is centered below the other two. The spongy body surrounds the urethra, and extends out the end of the shaft to form the glans. All three chambers contain small hollow areas that can fill with blood to produce an erection. Surrounding all three bodies is a semi-elastic membrane called the tunica albuginea. The arteries that feed blood to the penis are surrounded by smooth muscle fibers that normally limit blood flow to the penis. When a man is aroused by thought, sight, or physical stimulation, the muscle fiber relaxes and blood flow into the penis increases. The spongy tissue of the penis fills with blood, causing the penis to swell. The size of the erect penis is governed by the tunica albuginea membrane, just as a bicycle tire limits the expansion of the inner tube inside it. As with a bike tire, once the limit of the membrane is reached, further pressure results in firmness rather than expansion. The veins that drain the penis lie close to the surface, and are compressed by the erection, thus slowing flow of blood from the penis.

The only muscle in the penis is the smooth muscle fiber that controls erection, and this muscle can not be built up in the same way skeletal muscles can be. Even if this muscle could be strengthen, doing so would only serve to reduce blood flow to the unerect penis, making it smaller. In order to lengthen the penis the tunica albuginea and the spongy bodies would all have to be lengthened. The tunica albuginea is flexible to a point, but repeated stretching does not lengthen it the way the ear lobes can be lengthened.

Another issue that we need to be aware of is that the FDA does not regulate penis enlargement products in any way. The Dietary Supplement Health and Education Act of 1994 says that "dietary supplements" are not regulated so long as they do not make "disease or health claims." But a supplement can claim that it affects the "structure or function of the body." What this means is that a company can claim a product enlarges the penis (body structure) or increases the amount of time a man can have intercourse (body function) without having to worry that the FDA will examine the claims. If I put ground up parsley in a capsule, and sold it as an "ancient Oriental" penis enlargement formula, I would not be breaking any laws in the United States. Devices and exercises which claim to enlarge the penis are also essentially free from government supervision.

So, "buyer beware" is vital when looking at things that claim to enlarge the penis. There is no way to guarantee you are getting what you are sold, no proof it works, and no legal recourse if it does not work. Even worse, there is no guarantee the device, exercise or product is safe. Herbs are unregulated, even though some have been proven to have nasty side affects, so harm is possible.

So what is average? In the last ten years there have been several statistically and scientifically well done studies on penis size. The most famous of these studies, done by the University of California School of Medicine and reported in the Journal of Urology in 1996, found the average erect penis to be 5.1 inches (13cm) in length and 4.9 inches (12.5) in circumference. Studies done by the Department of Urology, University of Florence, Italy, and St. Mary's Hospital, London, as well as at other medical institutions, have give results that vary from 5.03 to 5.3 inches (12.78 to 13.46 cm).

• Pills: It only takes a bit of reasoning to understand why these could not work. What kind of drug could enter the blood stream and affect only the two specialized tissues in the penis? This would be like creating a pill that made the nose bigger!
  
  
• Creams: These seem a bit more reasonable, as they are targeted to the penis, but anything rubbed onto the penis is going to be carried away from the penis by the blood stream before it could get to the tunica albuginea or the spongy bodies. In fact, this has been a major hurtle for drug companies trying to find an impotence cure that can be rubbed on rather than injected. So far the best solution the drug companies have found is to insert the drug into the urethra (ouch).
  
  
• Surgery: There are two techniques that doctors can perform that do actually add size, but both are full of risks. For more length a doctor can cut the ligaments that attach the penis to the pelvic bone, and then move the penis outward some. This gains a man only about an inch, risks infection, and can leave the penis less stable because it's no longer anchored. For more width, fat can be injected into the penis. Unfortunately the fat does not stay put, and it can become lumpy or gradually leave the penis.
  
  
• Stretching exercises, weights, and stretching devices: Those promoting these technics offer a variety of explanations for how they work, but most of these explanations are contrary to the facts about how the penis is constructed. Some parts of the body can be enlarged by mechanical stretching, but this has never been shown to occur with the penis, and most experts doubt the tissue involved can be expanded in this way. Still, given the theoretical possibility, and the lack of independently verified studies of any of these techniques, there is no valid science to support saying these methods don't work. On the other hand, there is also no valid science to support saying the methods do work. What has also not been determined is if these methods can cause any permanent harm. Some urologist have voiced concerns about scaring, nerve damage, damage to the blood vessels, and Peyronie's disease (bent penis syndrome). While there are isolated claims of such damage, the evidence to date is far from conclusive. In time we will know if these methods are safe or harmful, but it will take two decades to conclusively prove safety, and if it's not safe what will those who went ahead and tried these methods do then?
  
  
• Jelqing: The Jelq is the most common method of penis enlargement being touted today. Basically jelqing consists of a "milking" motion down the penis that is supposed to gradually increase both length and circumference. A study of sites advocating this technique sends up several red flags.
  
  
  • The technique is said to be something used by men in the Middle East for centuries. But no one can back that claim up, and when WebMD.com researched jelqing they reported that "Sex historian Vern Bullough says he has never heard of it, and queries to the Kinsey Institute and professors of Middle Eastern studies at several universities shed no more light on the matter." (article no longer available)
    
    
  • Many sites suggest that enlargement is cause by breaking down and building up the tissues of the penis just like you exercise to make you biceps larger. But there are no tissues in the penis that respond this way.
    
    
  • The specifics of how to jelq vary widely from site to site. Some insist it won't work unless done with a full erection, while others warn that doing it with a full erection will cause damage.
    
    

So, does size really does matter, and can a penis can be too big? We have heard from several men and women who have problems enjoying sex because his penis is large - it may be a rare problem, but it does happen. The book "The Kinsey Institute New Report on Sex" (1990) says that more women report concerns and apprehension about too large a penis than report being unhappy with a smaller penis. Comments from members of The Marriage Bed e-mail list when penis enlargement was discussed show a similar concern (paraphrased to prevent identification):

I do not EVER care to see my husband larger than he is now.

I am 6.25 by 6.25 and my wife say if I make it bigger I won't be having sex with her.

I agree about not wanting my husband to get bigger. He is a 6 and 3/4 and that's as big as I care to go.

My wife wants me to get a reduction. She said she was impressed at first but, now says I am too big.

And finally, this thought "My first husband's penis was larger, but my current husband satisfies me far more often than the first husband ever did." This woman was not saying the smaller penis was better, rather she was saying her second husband was better because he was more loving. A loving caring man is the most important thing for a woman's sexual pleasure, and skill at what he does in bed is far more important than what he does it with. A dozen extra kind words each day and a few more minutes of foreplay will do more to increase a woman's sexual desire and pleasure than an extra inch or two of penis ever could.