Precocious Puberty and Why it Matters

Puberty is happening at younger and younger ages.

“What we’re seeing in our offices, and what the research is showing, is concerning. A shift as dramatic as this has implications for health in the short and long term, including diabetes and risk of cancer,” says pediatric endocrinologist Aviva Sopher, MD, associate professor of pediatrics at Columbia University Vagelos College of Physicians and Surgeons. 

“Children who start puberty too soon have emotional and social challenges too, because they look older than they are. Precocious puberty is an issue to be addressed.”

We spoke with Sopher to learn why precocious puberty is becoming more common and why it's a concern.  

Puberty basics  

Puberty is the body’s transition from childhood to adulthood. It’s a years-long process that leads to reproductive capability. During puberty, people have growth spurts, their genital organs mature, and secondary sex characteristics develop, including breast development in girls and people assigned female at birth and voice deepening and facial hair growth in boys and people assigned male at birth. 

The onset of puberty is controlled by a protein called kisspeptin, which stimulates the hypothalamus, a part of the brain, to release the hormones that get puberty started. 

The age of puberty  

• In girls and people assigned female at birth, puberty usually starts between the ages of 8 and 13 years with breast development. 
• In boys and people assigned male at birth, puberty usually starts between the ages of 9 and 14 with testicular enlargement.  

Puberty that starts earlier than these age ranges is called precocious puberty. Puberty that starts after these age ranges is called delayed puberty.  

Puberty generally ends two to five years after starting. 

Puberty is starting earlier in girls 

An analysis of international studies from 1977 to 2013 showed puberty in girls and people assigned female at birth has started about three months earlier every decade (about one year earlier every 30 years). Other studies show the shift is even more substantial in recent years, largely due to the COVID pandemic, the increased prevalence of childhood obesity, and endocrine-disrupting chemicals in cosmetics and personal care products.  

Precocious puberty occurs 10 to 20 times more frequently among girls than boys. Currently, about four in 10 girls and people assigned female at birth undergo precocious puberty. 

Puberty is starting earlier in boys, too 

It’s easier to detect precocious puberty in girls, but about one in 10 boys and people assigned male at birth undergo precocious puberty, too. Early puberty in boys is detected by testicular enlargement in a physical exam with a doctor. In boys, however, it’s more common to have central nervous system tumors (abnormal growths) or disease cause the early start of puberty.  

Studies have shown boys, on average, experience earlier growth spurts by up to five months, earlier ejaculation by one year, and earlier voice breaks. In 1968, the average age of voice break was age 15; in 2020, it was age 13.

Issues with early puberty  

Earlier puberty has been associated with deleterious long-term health outcomes.

These include:

• metabolic disorders, such as insulin resistance, prediabetes, and type 2 diabetes 
• increased cardiometabolic risk, such as high cholesterol, high blood pressure, overweight, and obesity 
• increased risk of breast and endometrial cancer in girls and testicular cancer in boys 
• psychosocial difficulties  
• psychological and behavioral issues from confusion to social withdrawal to extreme anger or fear to major depressive disorder 
• shorter adult height 
• improper expectation from adults because of older appearances, leading to self-doubt, misalignment with peers, improper situations and relationships 
• increased risk of sexual abuse, especially for girls 

Effect of COVID pandemic on puberty 

Several studies show an increase in new diagnoses of precocious puberty in Italy following lockdown and months at home.  

Lifestyle changes included an increase in the use of electronic devices: the light produced by these devices can lower melatonin secretion, leading to precocious puberty. (Normally, melatonin levels decrease during puberty, which stimulates sex hormone production).  

Stress may have contributed, too. Increase in stress leads to an increase in cortisol, followed by a decrease in cortisol. When the body produces too much cortisol, it can slow growth, cause obesity and mood changes, and disrupt puberty. When cortisol levels decline, earlier onset of puberty may follow.  

Slowing puberty 

Most often, if puberty starts too early, it’s best not to do anything, especially for relatively older children or when puberty is not progressing rapidly. In some cases, if there is a concern a child will not be able to handle going through puberty due to their young age, or if their height prediction will be compromised, doctors can intervene with a medication to slow the process.  

If you think your child may be starting puberty too early or have questions about puberty, talk to your pediatrician and ask if it’s appropriate to see a pediatric endocrinologist.