Childhood seems to be getting shorter. Social media, leisure activities, and broader cultural shifts appear to be pushing adolescence-like behaviors to start earlier, leaving many young people seeming eager to grow up faster than before. But is this just a perception among parents, or is there also a biological basis for the trend? Some experts worry that certain signs of puberty — including the onset of menarche — may indeed be occurring at earlier ages.

At least among some American mothers, the concern has clearly taken hold. According to a Newsweek report, social media influencers are offering advice on how mothers can help improve their daughters’ habits in an effort to reduce the risks associated with early menarche.

A Mixed Picture

Data published in JAMA Pediatrics in 2020, which focused on thelarche rather than menarche, found that the age at puberty onset, assessed by physical or clinical examination of breast development, declined by nearly 3 months per decade from 1977 to 2013. The authors noted, however, that the findings varied by region, with an earlier onset reported in the US (8.8-10.3 years) and a later onset in Africa (10.1-13.2 years).

More recent local data reinforce the same trend. An article published in September 2026 in the American Journal of Human Biology examined secular changes in the age at menarche over nearly eight decades, along with variations by specific sociodemographic and anthropometric factors, in Spain’s Valencian Community. The study found a 1.9-year decline in age at menarche among participants born between 1931 and 2008, consistent with global evidence of a long-term downward trend.

The study also found that the mean age at menarche fell below 12 years in the younger generations. The authors noted, however, that participants were born in different locations and that puberty timing is a multifactorial process, with associations seen for continent of birth and BMI.

A Multifactorial Trend

The question that arises, then, is whether this trend is a normal, evolutionary pattern or whether there are indeed reasons to consider an environmental influence that should be investigated.

On this issue, El Médico Interactivo, part of the Medscape Professional Network, spoke with Raquel Oliva Sánchez, MD, specialist in gynecology and obstetrics, president of the private care section of the Spanish Society of Gynecology and Obstetrics, who clarifies that changes in girls’ development are a trend that is older than it seems. “During the 19th and 20th centuries, the age of menarche clearly decreased, mainly due to improvements in nutrition, health, and living conditions. In recent decades, the decline in the age at menarche seems more modest than the earlier onset observed in the start of breast development.”

However, the report clarifies that there are many factors to consider when evaluating this issue, before raising unnecessary alarms. “Lifestyle can play a role, especially through excess body fat and rapid weight gain during childhood. Adipose tissue plays a role in the hormonal signals that inform the body that it has sufficient energy to begin maturation. Research is also being conducted on psychosocial stress, sleep, physical inactivity, and exposure to endocrine-disrupting substances. However, there is no single cause, nor can the phenomenon be attributed to a specific food, cream, or behavior.”

For this reason, she emphasized one message: “We do not have any dietary, exercise, or cosmetic guidelines that have been shown to safely and predictably delay menarche in a healthy girl. We do know that preventing overweight and obesity through a balanced diet, regular physical activity, and sufficient sleep promotes healthy development and can avoid one of the factors associated with earlier puberty. The goal should not be to delay the first period, but to protect overall health.”

The Reality in Spain

According to the expert, Spanish studies place the age of menarche at approximately between 12.5 and 13 years old, with individual, familial, and population-level variations. Regarding which signs should actually be cause for concern, Sánchez clarified that it is not only the date of the first period that matters but also observing when puberty begins and how quickly it progresses.

Precocious puberty is defined as the onset of secondary sexual characteristics, particularly breast development, before age 8. In practical terms, families should be advised to seek medical evaluation if breast buds appear before age 8 or if pubic hair develops unusually early.

“In such cases, if we confirm central and progressive precocious puberty, treatment may be considered, with the primary goal of preserving final height and preventing development from being completed too early. And in most cases, we’re talking about rare situations. That’s why, rather than delaying anything, it’s a matter of calmly observing and seeking advice if something appears prematurely,” explained Sánchez.

At this point, she emphasized two ideas. The first is that the cases requiring consultation are few and far between, and even in those cases, the contributing factors remain diverse.

Genetics and family history play a significant role, but they interact with nutrition starting in utero and other factors such as exercise or stress. Environmental exposure to mixtures of chemicals during sensitive stages of development is also being studied. Thus, even inequalities in access to healthy foods, spaces for exercise, adequate rest, and healthcare can have an impact.

For all these reasons, despite trends on social media or the alarmist messages patients receive that prompt them to seek medical advice, she said, “blaming the family or a girl for early puberty is not scientifically fair and can lead to unnecessary guilt.”

This story was translated from El Médico Interactivo on Univadis, part of the Medscape Professional Network.