Many things influence growth and body development in people born male. Your height is determined by a combination of genes (traits passed down in families) and environmental factors, such as an unbalanced diet, malnutrition, economic status, and certain conditions. Most men reach their adult height by 18 years old, and only rarely grow more after that.
Most males reach their adult height after puberty, which starts around 9-14 years old and lasts until 16-18 years old. Peak height velocity, also known as a growth spurt, typically occurs around 12-15 years old. During growth spurts, males average about 11 centimeters (cm), or around 4.4 inches (in), of height every year.
Toward the end of puberty, the growth plates at the ends of long bones start to fuse (join) together, which stops you from growing and determines your final height. Growth plates are layers of cartilage (flexible tissue) that allow bones to grow longer. In boys, these plates stop growing between 14-19 years old.
When puberty ends can vary. However, the average age is around 16 years old. Some males may experience early puberty or faster growth, while others start later and may continue growing between 18-20 years old.
Rarely, some people have growth plates that naturally take longer to fuse. You can also continue growing due to certain health conditions, like gigantism, where a person continues to get taller into their early 20s.
A combination of genetic and environmental factors can influence male growth. This includes family history, poor sleep hygiene, nutrition deficiencies, and having certain health conditions. These work together to determine your final height.
Genetic and Environmental Factors
Your family and medical history, as well as physical and external factors, can heavily affect your growth and development, including:
- Polygenic traits: These are characteristics that are influenced by two or more genes. Your genetics are the biggest influence on your height. Current research suggests that about 80-90% height differences are determined by the activity of several genes from both parents.
- Nutrition: This is the second-most influential factor on height, next to genetics. Malnutrition, which is when you aren’t getting enough nutrients, specifically in childhood or during pregnancy, impacts growth. This can lead to a shorter overall stature.
- Sleep: Some studies suggest that not getting enough sleep during puberty can also affect overall height. While one night of sleep won’t affect you, there may be long-term effects on your height if you have frequent sleep challenges. However, evidence is mixed on this topic.
- Medications: Stimulant medications, which children take for attention deficit hyperactivity disorder (ADHD), may slow down growth at first and possibly cause a shorter stature. However, the effect of stimulant medication on overall height is unclear.
- Economic status: Children from higher socioeconomic backgrounds are less likely to experience malnutrition and more likely to eat healthy, which supports growth.
Conditions That Affect Height
Some conditions that may determine a man’s final height include:
- Genetic conditions: Certain genetic conditions can impact height. Marfan syndrome can increase a person’s height, while conditions like Down syndrome and Turner syndrome stunt growth.
- Endocrine conditions: These are conditions that cause hormonal imbalances that stunt growth and delay puberty. Examples include hypothyroidism and hypopituitarism, both of which cause the body to produce less growth hormone.
- Chronic (long-term) conditions: You may have a higher risk of stunted growth if you have cancer, heart disease, or arthritis.
- Skeletal dysplasia: This is a collection of about 400 bone and joint growth conditions. Spinal stenosis, which causes the spinal column to tighten, and kyphosis, which causes a curved spine, are two types. The impact these conditions have on bone and skeletal growth reduces height.
- Precocious puberty: This is a condition where boys 9 years old or younger go through puberty early. Early-onset puberty can cause rapid growth at first, then slow down. In this case, children may be tall when they’re young, but grow up to be shorter than average.
Men usually stop growing taller between 14-19 years old. However, some people do continue growing into their 20s, which can happen because of:
- Hormone deficiency: In some people, growth plates are naturally delayed in fusing and continue growing. These delays occur in males born with a deficiency in aromatase, a substance that makes the hormone estrogen. Estrogen is the main female reproductive hormone. However, it affects growth and development in both males and females.
- Gigantism: This is a condition that mostly affects men and raises the growth hormone, causing them to grow significantly taller than others and develop tumors. Men with the condition typically stop growing by 23 years old.
- Hemochromatosis: This is a genetic condition where iron builds up in organs. It can damage organs, and the extra iron causes additional growth in people who have the condition.
- Acromegaly: This is a rare genetic condition in which the pituitary gland produces too much growth hormone. As a result, bones and tissues in the body grow larger, with common signs including swollen or larger nose, hands, feet, or ears.
It’s natural for people to grow and develop at different paces. However, it’s important to know when things may not be progressing as they should. Broadly, children and adolescents may require help if they aren’t hitting developmental milestones, or gaining the physical, mental, and emotional skills they need by certain ages.
With male growth and physical development, signs you may need additional help include:
- Grow 4 cm (about 1.6 in) or less in a year before puberty
- Develop pubic, armpit, or facial hair at nine years old or younger
- Have testicles that are smaller than about 1 inch at 14 years old
- Have a smaller, lighter, or immature penis at 13 years old
- Have little to no body hair by 15 years old
- Have no pitch changes in their voice during puberty
- Don’t gain enough weight for their age
- Have a stature that’s shorter or taller than 95% of people
Growth or developmental challenges can lead to serious complications, including:
- Shorter stature
- Psychological, emotional, and social difficulties
- Developmental delays
If you are concerned or your child is showing any of these signs, it’s important to seek care.
People born male grow the most during puberty, which is between 9-14 years old, and usually reach their adult height by 18 years old. However, some may keep growing, especially if they start puberty late. Certain health conditions can also influence growth, with some people getting taller in their early or mid-20s. How tall boys become is mostly determined by genetics, though environmental factors like nutrition and chronic condtions also play a role.
