Childhood is becoming ever shorter and ending at the tender age of 12, a survey by Netmums has found.
According to the poll of over 1,000 parents by the website, over 70% said their child was no longer childlike by the age of 12.
Almost all of the parents felt that children today were under far greater pressure and grow up faster than previous generations.
The change is blamed on a toxic mix of peer pressure, celebrity culture and the media.
Just under half the parents of daughters (45%) said their child was under immense strain to be thin. They also noted that their daughters were worried about how popular they are and how many Facebook friends they have.
Over a quarter felt their daughters were being pressured into an interest in sex and boyfriends too soon.
Boys are also under pressure, the survey found, to be "macho before they were ready" and believe "appearance was the most important thing about someone".
A third of parents think exposure to the internet has played a role in their children growing up too fast, while others admitted concern about celebrity culture and the obsession with sexualised and body conscious stars.
Over half of parents (54%) were angry that fashion retailers provided clothes aimed at teenage girls that "can be too sexual, such as overtly short skirts or crop tops".
Tweens today are also indulging in different hobbies from their parents' generation, the survey found.
Most of the parents (83%) said they were still childlike at the age of 12 and that their favourite past-time was playing outdoors with friends. This compares with the top past-time of today's tweens of playing alone on an iPad or tablet.
Only 23% of children spend time reading compared to 41% of their parents when they were the same age. While 39% of parents said they listened to music, this compared to only 17% of the children.
Netmums co-founder Siobhan Freegard says: "The pace of modern life is so fast that it is even snatching away the precious years of childhood. A toxic combination of marketing, media and peer pressure means children no longer want to be seen as children, even when we as parents know they still are.
"It's shocking our study shows childhood ends by 12 years old. Children need time to grow and emotionally mature in order to cope with what life throws at them.
"There needs to be a radical rethink in society to revalue childhood and protect it as a precious time - not time to put pressure on children to grow up far too fast."