Companies and shops marketing toys as either for boys or for girls are damaging the economy by causing fewer women to take up science and engineering jobs, a minister has said.
Consumer affairs minister Jenny Willott said: "The way we play as children informs the skills we develop."
Toys marketed to boys boosted interest in science and maths, she claimed.
And as long as girls shy away from those subjects, UK businesses will "miss out on vital talent", she warned.
"Girls and boys take into the classroom assumptions that they develop as part of playing," the Lib Dem minister told MPs in a debate in MPs' secondary debating chamber, Westminster Hall.
"Boys who have routinely experienced the sense of accomplishment associated with designing and building something, which can often can come from playing with what would be seen as a boy's toy, feel more at home with subjects such as maths and science, which utilise such skills more," she continued.
"By the time they get to university level, boys and girls are strongly segregated in some areas with, on the whole, boys dominating in the subjects that can lead to the most financially lucrative careers."
She claimed that "22% of the gender pay gap can be explained by the industries and occupations in which women work", adding: "But it also costs our economy significant amounts."
Ms Willott explained: "There are skills shortages across the science, technology, engineering and maths sector, but as long as girls continue to feel that that world is not for them, our businesses will continue to miss out on vital talent that they need for future development.
"Put simply, we cannot afford not to allow girls the opportunity to enjoy and pursue the whole range of subjects, starting right at the beginning with their learning through play."
Society should therefore aim not to make boys who want to play with a pushchair and girls keen to kick a football feel guilty or ashamed, she argued.
"A boy who has never had a sewing kit might never discover his talent for design and a girl who has never had a Meccano set may never discover she has real potential as an engineer.
"Clearly not every girl that plays with Lego is going to be an architect... but why should we limit girls' aspirations at so early an age by making it so rigidly defined?"
Toy shops gave off clear signals, the consumer affairs minister said: "The shelf may say 'girls' or 'boys' on it, or otherwise girls' and boys' toys may be colour-coded or displayed in separate aisles.
"What message does that send out? What are we telling our children? We are telling them that girls and boys are different, that they like different things and that they have different interests and skills.
"We are telling them that their gender defines their roles in society and their dreams about the future."
The debate was led by Labour frontbencher Chi Onwurah.
"Before entering Parliament, I spent two decades as a professional engineer, working across three continents," she told MPs.
As a consequence, she had become accustomed to working in a male-dominated environment.
"But it is only when I walk into a toy shop that I feel I am really experiencing gender segregation," she said.
"At some point over the past three decades, the toy industry decided that parents and children could not be trusted to figure out what to buy without colour-coded gender labelling."
Science-themed toys were often labelled "for boys", with products like miniature dustpans and brushes marketed towards girls, she told MPs.
"What happened? Did someone dye the Y chromosome blue in the 1980s or force the X chromosome to secrete only pink hormones?
"No. This aggressive gender segregation is a consequence of big-company marketing tactics.
"As every successful marketeer knows, differentiation makes for greater profit margins and segmentation gives you a bigger overall market, so with three-year-old girls only being able to choose pink tricycles, then the manufacturer can charge more for that special girly shade of pink and the premium princess saddle.
"And of course, that trike cannot be handed over to a brother or nephew, ensuring further sales of blue bikes with Action Man handlebars. It has now got to the point where it is difficult to buy toys for girls, in particular, which are not pink, princess-primed and/or fairy-infused.
"Why should girls be brought up in an all-pink environment? It does not reflect the real world. I should say that had anyone attempted to give me a pink soldering iron when I was designing circuit boards, they would have found my use of it not at all in accordance with their health and safety."