People who begin drinking alcohol during puberty are more likely to become hooked, researchers have warned.
Many parents think that supervised early drinking encourages children to have a more responsible attitude to alcohol.
But a study has found that those who begin to drink during puberty, rather than afterwards, tend to drink more later in life.
The team from the University of Heidelberg in Germany reached the conclusion after analysing the drinking habits of 283 young adults.
Study author Dr Miriam Schneider said that while most teenagers have their first alcoholic drink during puberty, previous studies had focused simply on drinkers' age when they began, and not their individual stage of development.
She said that tracking what phase of puberty people were in when they had their first drink "may represent a stronger and better indicator for subsequent alcohol-related problems than simply the age."
She and her colleagues determined what stage of puberty participants had reached "at first drink", and then recorded their drinking behaviour at ages 19, 22 and 23. The human research was supplemented by similar work on rats.
"Both studies revealed that those individuals that initiated alcohol consumption during puberty tended to drink more and also more frequently than those starting after puberty," Dr Schneider said.
She claimed changes in the developing brain could explain the connection.
"It is during puberty that substances like drugs of abuse - alcohol, cannabis, etc. - may induce the most destructive and also persistent effects on the still-developing brain, which may in some cases even result in disorders such as schizophrenia or addiction.
"Prevention work therefore needs to increase awareness of specific risks and vulnerability related to puberty."
Dr Schneider's colleague Dr Rainer Spanagel agreed.
"Puberty is a phase in which the brain reward system undergoes major functional changes. Therefore, during puberty the brain is in a highly vulnerable state for any kind of reward, and drug rewards in particular."
The German study echoes the warning made by a senior psychologist to MEPs earlier this month.
Dr Aric Sigman said adults needed to realise that alcohol was more damaging to the young brain and body. He stressed that studies showed that the earlier a child is introduced to drink, the greater their odds of becoming an alcoholic.
In a report to an EU think-tank on childhood and adolescence, Dr Sigman said it was "imperative" that parents delayed the age at which they introduce their children to alcohol.
He said that "even in small amounts", alcohol may have long-lasting effects on the brain, which continues developing long after the body matures.
Dr Sigman, a fellow of the Royal Society of Medicine, said parents were wrong if they believe that by giving their children small amounts of alcohol at home, they were teaching them to drink responsibly. In fact, research suggests that early exposure to alcohol primes the brain to enjoy it more.
Eric Appleby, of the charity Alcohol Concern, said: "It may feel that introducing children to alcohol in a safe and controlled environment at home is the right thing to do, but all the research indicates that the younger someone starts drinking, the more likely they are to have problems with alcohol in later life.
"The Chief Medical Officer advises that an alcohol-free childhood is the safest option."
- DAILY MAIL