It calls upon the Government to prohibit sexualised media, marketing and products aimed at or easily accessed by children under 16 years of age.
The petition is part of the Bye Buy Childhood campaign launched last year by the Mothers' Union in response to widespread concerns about the sexualisation of children in Britain.
Kempsell said, “We are delighted that the Government has already taken action to tackle the commercialisation and sexualisation of childhood through the Bailey Review.
"We would like to see this Review make strong recommendations to Government to ensure childhood can remain a precious time free from commercialisation.”
Joining Kempsell at Downing Street were MPs Helen Goodman, David Morris, Fiona Bruce and Jim Dobbin.
Speaking after the event, Goodman said: “Once again Mothers Union is at the forefront of a really important campaign to support families. I’m giving the Bye Buy Childhood campaign my total support.”
The Bye Buy Childhood campaign launched last September off the back of research by the Mothers' Union which found that 80% of parents in Britain believe media and marketing with sexualised content are too easily accessed by children and are making them sexually aware at too young an age.
The Bye Buy Childhood campaign is encouraging parents and the wider family to think about the influence of commercialisation within the home and to take positive action to challenge instances of inappropriate marketing or selling.
It is also asking them to do their part in holding the Government accountable on the pledges made to address the commercialisation and sexualisation of children.
Parent Tim Atkins was also there to present the petition with his nine-year-old daughter, Ella.
He said: "I am very aware of the fact that she, and we as parents, are constantly exposed to pressure from companies to buy unnecessary or unsuitable products for our children.”