Two in five adults believe boys and girls should be allowed to wear either trousers or skirts to school, according to a poll.
Research by YouGov Omnibus found that 40% of adults quizzed believed pupils of either gender should be permitted to wear skirts or trousers to school.
A total of 31% said girls should be allowed to wear either skirts or trousers but boys should only be allowed to wear trousers.
The traditional policy of boys in trousers and girls in skirts was selected by 9% of the respondents and 7% said boys and girls should only be allowed to wear trousers.
Those aged 18 to 24 (46%) are significantly more likely than the country as a whole to think boys and girls should be allowed to wear either trousers or skirts.
The survey also questioned pupils aged six to fifteen and revealed the children shared broadly the same opinions as the grown-ups, with 41% saying they should be allowed to wear either.
However, there was a slight difference between boys and girls on the question of girls being allowed to wear trousers or skirts.
Girls were more likely to support the policy, with 47% responding positively to the question compared to 37% of boys.
However, the results showed girls were slightly less likely to think boys should have to wear trousers and girls should have to wear skirts, with just 7% supporting this policy compared to 12% of boys.
Ben Glanville, head of Omnibus UK, said: "A brand new school year signals that summer is almost over. The issue of what schoolchildren should be able to wear as part of their uniform has gained extra prominence in recent years.
"Our survey data indicates that parents and children both feel passionately about the subject while it's more likely for girls to think both genders should be able to wear trousers or skirts, there is still strong support from boys which shows that many are in favour of having the freedom to choose when it comes to their school uniform."
YouGov Omnibus questioned 3,849 adults and 586 children aged six to 15.