GIRLS are throwing out toy dolls at a younger age and a leading adolescent psychologist says it is yet another sign that childhood is being eroded.

Generation Z, aged 0 to mid-teens, is a generation of "up-agers", says Mark McCrindle, a social researcher in Sydney.

Mr McCrindle surveyed 2500 Australians and found that while the mothers of today's children stopped playing with dolls between the ages of 10 and 11, their daughters were discarding dolls at an average age of six or seven.

"These kids are 'up-ageing', they're moving into a technological world much earlier and it's partly coming from their peers … but it's also partly coming from parents who are pushing their children towards more structured educational toys," he said.

Five-year-old Ava Hampshire has an enviable cache of dolls, many of which have been inherited from her older sister Helena, now 10.

If Ava follows her sister and peers in the current trend, within two years she, too, will put aside her Bratz and Barbies in favour of a Nintendo DS, an iPod and borrowed time on her mother Viv's laptop.

Ms Hampshire says she finds herself saying "no" a fair bit, most recently to Helena's requests for a mobile phone and an expensive bracelet a lot of her friends are acquiring.

The activity the sisters still do have in common is watching music videos on television, but Ms Hampshire says she often finds herself switching the channel.

"Ava loves dancing ... she does the whole Kylie thing, but some of the clips are quite raunchy."

Not even the raunchy dolls launched a decade ago to claw back the "tween" market have arrested the tide. More than 66 per cent of the parents of girls surveyed said they were concerned at the messages skimpily clad and heavily made-up dolls might send to their daughters, yet almost half had bought such a doll for their child.

By age seven, however, most generation Z girls had ditched them in favour of more sophisticated gadgets.

Child psychologist Michael Carr-Gregg, who is writing a book on generation Z, said the up-ageing syndrome, fuelled by the premature sexualisation of children, has resulted in a generation of young girls deeply dissatisfied with their age, no matter how old they are.

"You take your average six- or seven-year-old girl and they're into High School Musical - they want to be 10 or 12. The 12-year-olds are trying to be 16 and the 16-year-olds think they are 21. There's not many girls out there who are happy with their age any more. There's widespread dissatisfaction at being a child."

He said pushy, competitive mothers were partly responsible because they encouraged their daughters to look more mature than their age, dress in fashionable but sometimes age-inappropriate clothes and discard play that did not appear to have an educational benefit.

He said the survey highlighted the problem of cashed-up, time-poor parents.

"These children have zero resilience. They're growing up as little automatons. These kids will eventually breed and I'm terrified what that generation might be called - generation Neurosis I suspect."