The colleague’s son used to think his mother’s colorful tufts of hair were pretty. Now she asks, “Mom, can’t you look normal?” When parents suddenly become “annoying,” their offspring are probably in their teens.

This is when the body produces more sex hormones: estrogen and progesterone in girls and testosterone in boys. These cause physical and psychological changes. Mood swings are normal – as is the need to distance themselves from parents. Externally, pubic hair develops in both sexes. Girls’ breasts grow, followed by menstruation. Boys’ voices break, their testicles and penis grow and they ejaculate for the first time.

A year ago today

All of this is taking place at a younger age today than in the past. A study found that in 2013, puberty in girls started on average almost a year earlier than in 1977. Boys also tend to hit puberty earlier, although the study’s results are not as clear as for girls.

It was not until the 19th century that young women in Europe had their first period at the age of 17, while in the early 1960s it was around 13. Today, the average in Germany is 12.8 years, reports Bettina Golke, head of the Pediatric Endocrinology Department (KEDAS) at the University Hospital of Bonn in Germany.

The increased standard of living could have played a role in this development. Under better conditions, offspring may grow earlier. “However, puberty does not begin with the first menstruation, but with the development of the breasts,” emphasizes the scientist.

But why has that time moved forward by about a year in just four decades? There are several reasons for this and not all of them can be clearly demonstrated.

Obesity in the age of the corona virus?

Research has shown that overweight children enter puberty earlier. In their fat tissue, more of the messenger substance leptin is produced and this signals the brain to start puberty.

The fact that children moved less and gained weight could be one of the reasons why significantly more girls went through early puberty during the coronavirus pandemic. It is the development of external sexual characteristics in girls before the age of eight and in boys before the age of nine.

“In addition, the whole lifestyle had changed, such as the day-night rhythm, children had more psychosocial stress and spent more time on the computer – and blue light, as animal studies have shown, has an effect on hormones.

What is the effect of chemicals on adolescence?

Scientists suspect that chemicals from our environment affect puberty. For example, the pesticide DDT has been shown to lead to early onset of menstruation. Substances in personal care products, such as phthalates, parabens and other phenols, are also suspected of causing earlier puberty, especially in girls.

The global trend toward earlier and earlier onset of puberty has developed over such a short period of time that it cannot be explained by genetic changes.

However, it is not clear exactly which substances are responsible for this. And that’s because: “There are well over 100 different substances that could be potential causes, as animal experiments have shown – and we’re exposed to a whole range of substances.” In addition, there is always the question of dose: an amount that is still considered harmless in animal experiments could certainly have effects on children.

Lavender oil and soy milk affect

Essential oils can also have an effect on hormones – and thus the onset of puberty. For example, girls and boys experienced early breast development after using lavender products. Laboratory tests have shown that 65 essential oils contain certain substances that have a hormonal effect on human cells. Breast growth slowed in all children when flavored products were discontinued.

Soy products also have a hormonal effect. Soy contains so-called phytoestrogens, i.e. plant substances, which are similar to the human hormone estrogen – just like beer.

Their effect on the onset of puberty has not yet been proven. However, in one study, women who were fed soy protein as infants reported significantly longer periods and more severe menstrual problems. The German Society of Pediatrics and Adolescent Medicine therefore advises against giving infants a soy-based diet as a standard.

Only children go through puberty earlier

And something else seems to affect the onset of puberty: On average, only children go through puberty earlier than children with siblings, half-siblings or step-siblings, a Danish study shows. One explanation could be that when passing down family genes, only children cannot rely on siblings – so their body prefers to rely on its own reproductive capacity at a young age.

Sources: Worldwide Secular Trends in Age at Pubertal Onset Assessed by Breast Development Among Girls:

https://jamanetwork.com/journals/jamapediatrics/fullarticle/2760573