The onset of puberty is determined by a string of factors, such as environment, physiology and heredity, but just how they interact remains a mystery. It is also unclear why puberty is starting at ever-younger ages across Europe and other parts of the world.
A three-year project, called Pioneer, will investigate the theory that a greater intake of calories has a significant role in this trend. It will also look at hormone-like substances in the environment.
For example, researchers at Sweden's Karolinska Institute will study whether the production of male and female sexual hormones is greater in overfed animals than in undernourished ones.
"It's important to find out the cause of this problem as the early onset of puberty affects a large number of children and can eventually give rise to new reproductive patterns," said Professor Olle Söder, vice coordinator of Pionner at Karolinska.
In an interview with the EU research information service, Cordis, Leo Dunkel from Finland's Kuopio University Hospital noted that genetic pre-disposition is core to puberty onset. But fat mass and sensitivity to insulin are thought by some to be responsible for precocious puberty.
A third stimuli for the onset of puberty may include stress, adoption, migration, nutrition and endocrine-disrupting chemicals.
Studies have born out the migration theory. For example precocious puberty in industrialised countries appears to be most prevalent among children born in developing countries and then adopted by a Western family.
A non-European partner involved in the project, Zulfiqar Bhutta from the Aga Khan University in Pakistan, is aiming to find an explanation for this.
Also, contact with contaminants was thought by many to be responsible for a huge upsurge in the number of cases detected in Puerto Rico in the 1980s. Some suspected that growth promoters had somehow entered the food chain, but as such substances are illegal in Europe, this would not explain all incidents.
Similarly, a high percentage of those experiencing puberty prematurely in the US are overweight. But this is by no means the case for all sufferers.
The project partners held their first meeting on 21 March. It is being coordinated by Sari Mäkelä from the University of Turku in Finland, and involves 11 other research groups.