A majority of pupils in the area now attend trousers-only schools with eight Ipswich schools instituting a gender-neutral policy, it is claimed.
Meanwhile Crawshaw Academy near Leeds is "consulting on implementing a gender-neutral uniform (trousers only)", The Sunday Times reports.
And Phillips High School in Bury has announced that girls starting at the school this September will have to wear trousers with existing pupils adopting the new policy next year.
The move has been branded "crackers" by one parent, who said there is nothing wrong with the existing uniform for girls.
Girls due to start Philips as Year 7s in the autumn term will not be allowed to wear the same navy knee-length skirts worn by existing pupils.
Diane Burdaky, whose daughter Annabelle is in Year 8, claims parents were never consulted about the changes.
"There was no letter or email. No word or consultation from the school at all.
"I looked on the website and there was a notice saying all new students from September will have to wear trousers and then the rest of the school will follow in September 2019.
"I'm all for a school uniform policy. I think it's very important that parents work with the school to make sure the rules adhered to.
"My problem is why this has happened. I can't think of any reason why girls shouldn't wear them. For years girls have rolled their skirts up as soon as they've left the house. We all used to do it.
"But you can't control what they do when they leave the house. It's up to the school to police it when they're there.
"I feel strongly that parents should have been consulted and given a valid explanation.
"It's good to give girls the option of wearing a skirt or trousers, but I don't understand the need for a total ban. I think it's crackers."
Tony Smith, head of Priory School, said last year: "The reason for the uniform change initially is about equality, and decency.
Our students will all now wear the same uniform. 'It is a much more decent uniform and it is far less likely to lead to abuse.
"It is a gender neutral uniform, and we've thought carefully about that, ensuring that is was gender neutral.
"We have transgender students in the school and we have an increasing number of students who are at that crossroads of understanding around their gender.
"So this uniform removes the need for anyone to make a decision about whether they wear a so-called male or female uniform.'
But the move was slammed by the school's former pupil Piers Morgan, who said: 'It's disappointing to see one of my old schools getting sucked into this gender neutrality nonsense, which is being driven by a tiny minority of people.'
"Let boys be boys and girls be girls, and stop confusing them in this ridiculous way."
It comes after £18,000-a-year Immanuel College in Hertfordshire brought in make-up experts to teach pupils how to apply it.
They have been introduced after one 15-year-old pupil revealed that she was suffering anxiety over a skin condition and wanted to learn how to use beauty products.
The co-educational school, which has 570 pupils, has also lifted a ban on make-up for under-16s.
