Pubic hair is often the first body hair to grow during puberty. As puberty progresses it becomes courser, curlier, and darker. Pubic hair begins as sparse hair that grows on the pubic bone just above the base of the penis at the 10 o’clock and 2 o’clock positions (see stage 2 below). After this early stage the pubic hair on each side of the penis begins spreading inward to cover the area directly above the penis, downward towards the scrotum, and up the pubic bone toward the lower abdomen. By the end of puberty, pubic hair will spread to the thighs and behind the scrotum up into the crack of the buttocks. In fact, pubic hair spreading onto the thighs is one of the final signs that puberty is nearing its end. [i]
Pubic hair growth on the pubic bone itself (between the penis and lower abs) occurs in almost 100% of adult men and really doesn’t vary much from one man to the next. The area right around the pubic bone tends to have the densest hair growth (below left). Less dense pubic hair will often spread out to the left and right creases of the leg (below right), and in some men may be fairly dense in these edge areas as well. However, pubic hair is typically the densest right above the penis at the 10 o’clock and 2 o’clock positions where pubic hair growth began during puberty.
In rare cases adult men will have a “bipartite” pubic hair pattern – public hair that stopped spreading during puberty. The hair is econfined to either to the 10 o’clock and 2 o’clock positions (below left) or an area directly above the penis that is relatively bare (below right).[i] Men with bipartite patterns usually have no abdominal hair.
For most men, hair spreads from the pubic bone down towards the scrotum, especially the sides. Scrotal hair is less dense than hair on the pubic bone, thus making the scrotum skin fairly easy to see through the hair.
Scrotal hair grows on the majority of men. Our survey found that 93% of men reported having scrotal hair with 66% saying their scrotum was covered extensively by hair. This varied by racial groups with White/European men having scrotal hair 96% of the time compared to 92% in Native American/Indian/Pakistani men. The least likely were Asian, Black/African, and Hispanic men at 88-89%. Extensive scrotal hair growth was even more markedly different among racial groups--78% of White/European men having hair on the majority of the scrotum, compared to other racial groups with 46-60% reporting extensive hair growth.
Hair can grow on three main areas of the scrotum – the sides of the scrotum, the center portion of the front of the scrotum, and the center portion of the back of the scrotum.
The sides of the scrotum are the most common areas to find hair,. Even in men who grow hair all over the scrotum, the sides are often the area with the most hair. The middle on the backside of the scrotum, on the other hand, is the area least likely to have hair. In fact, men rarely, if ever, grow scrotal hair here. Even in men who have hair all over the scrotum, this area on the back oftentimes has less hair than the sides and the front.
This results in four main categories of scrotal hair growth:
Bare - no hair on the scrotum
Sides Only - hair growth only on the sides of the scrotum
Bald Backside – hair growth on most of the scrotum except the backside
Entire - hair on surfaces of the scrotum
Below is a table showing the various hair growth patterns (front of scrotum on left and back of scrotum on right).
Although most men think of the penis as being “hairless,” nearly all men will have some sparse hairs on some portions of the penis. This hair is confined to the shaft of the penis, especially near the base of the shaft where the majority of pubic hair is found. Hair on the base of the penis resembles pubic hair in thickness and length. However, hair found further up the shaft of the penis is typically very sparse and often much shorter than other pubic hair. Unlike other ethnic differences, Asian men are the most likely to have penile hair (64%).
There are four main classifications of penile hair patterns:
Base Only - hair growing only at the base of the penis near the pubic bone
Underside Only - A few hairs grow up the underside of the penis
Underside & Sides - A few hairs extending from the underside onto the left and right sides of the penis
Across the Top - A few hairs extending from the sides across the top of the penis
Because penile hairs are so sparse, some men may have a “mixture” of patterns – one on the left side and another on the right side. For example, a man may have hairs running up the underside of the penis then notice one or two hairs on the left side of his penis (third pattern) but no hairs growing on the right side (second pattern).
PUBIC HAIR GROOMING
Grooming of pubic hair is becoming more common and it is worth noting some risks. A study[ii] was performed looking at the incidence of genital injury due to grooming. This study involved over 4,000 men and found that two-thirds of these men had trimmed, shaved, or removed pubic hair.
The incidence of injury was actually quite high, with over one-fourth of men indicating that they had sustained an injury from pubic hair removal. The most common areas of injury were the scrotum (67%), penis (35%), and pubis (29%). Men who removed all of their pubic hair, rather than simply trimming hair, were 11 times more likely to have an injury. The incidence of individuals who had an injury and had to seek medical attention was 1.4%.
Shaving or using electric clippers can be perhaps the most dangerous. Cuts can bleed profusely and infections can set in. This can especially occur on the scrotum since the scrotal skin is so thin (hence the reason men have twice as many hair removal injuries to the scrotum compared to the penis or pubis). In addition, the skin on the scrotum and penis is constantly being stretched when the cremaster muscles cause the scrotum to tighten and loosen. Cuts on the penis are difficult to heal since men regularly get erections.
Long story short, great care should be taken if grooming the pubic region. It is significantly safer to trim with non-mechanical clippers rather than removing all pubic hair with electric clippers or a razor.
[i] Setty LR, Journal of the National Medical Association, The Bipartate Pattern of Pubic Hair, May 1964 56; 261-2.
[ii] Truesdale MD et. al., Prevalence of Pubic Hair Grooming-Related Injuries and Identification of High-Risk Individuals in the United States, JAMA Dermatology, 2017 Nov 1; 153(11): 1114-21.
All images on this page are original design