Youngsters are being exposed to sexually-explicit messages and photos on the internet, according to a new poll.
Some 25% of 13 to 15-year-olds have seen sexually explicit images online while 28% have been sent sexual pictures on a mobile phone.
More than one in four (28%) children aged 10 to 12 have read alcohol-related posts on social networking sites, while 37% of 13 to 15-year-olds have viewed photos of their friends drunk.
Some 13% of 13 to 15-year-olds admit they have come under pressure to drink alcohol.
The poll, of 800 parents and 600 children, was carried out for the industry-funded charity Drinkaware and parenting charity Family Lives.
It found 87% of parents thought their children were growing up too quickly, with 86% saying increasing exposure to technology was influencing that.
Some 74% believed the issues facing their children were more serious than those they experienced at the same age, with many citing sex, drugs and smoking.
But children themselves highlighted other problems, including underage drinking and "sexting" - sending and receiving sexually explicit text messages.
Of those children aged 13 to 15 who were surveyed, 31% admitted consuming alcohol while 28% had encountered sexually explicit text messages.
This compares to 15% who said they had smoked and 4% who had taken drugs. Of those parents surveyed, 54% had never heard of "sexting".