A majority of parents in the UK believe children are being exposed to "inappropriate" content on television before the 9pm watershed, according to research published.
An online study of 1,004 parents of children under the age of 18 years old has shown that 67% believe that "inappropriate" content is broadcast before the 9pm watershed.
A further 80% told the Mothers' Union survey that they believed films and video games with sexual or violent themes can be accessed too easily by children.
The research conducted last month also showed that 80% of parents believe that television, films, magazines and the internet make children sexually aware at a younger age than they would be otherwise.
The findings are included in the charity's report Bye Bye Childhood detailing the impact of advertising and marketing on children's happiness.
The charity has called for a ban on marketing or selling goods of a sexualised nature to children under 16 years of age.
It also wants to see safeguards to ensure children under 16 are shielded from marketing and displays of sexualised products.
The charity said it was concerned about the recruitment of children on the internet for so-called "peer-to-peer" marketing.
Under these schemes, children are encouraged to pass email addresses of friends to advertisers and promote products to other children in the playground, the report said.
Rosemary Kempsell, Mothers' Union worldwide president, said: "Mothers' Union is concerned at the increasing levels of marketing aimed at children."