Rishi Sunak has promised schools volition person guidance connected policies for transgender pupils for the summertime term.
The Prime Minister intervened aft a teaching national said its members were navigating a 'minefield' astir gender.
He was asked astir a study from a centre-right deliberation vessel Policy Exchange which looked astatine 154 English secondary schools.
It recovered lone 39 of them reliably informed parents erstwhile pupils identified arsenic trans oregon questioned their gender,
Eighty-seven schools recovered parents were not reliably informed, 14 did not supply capable item and a further 14 chose not to respond.
The authors of the report, written arsenic portion of the deliberation tank's Biology Matters Project, submitted a Freedom of Information (FOI) petition to 304 of England's 24,000 secondary schools.
The schools were chosen astatine random. Any peculiar schools which were selected were discounted from the study arsenic Policy Exchange said "many of the issues raised are not applicable oregon relevant" to them.
Schools were asked a bid of questions astir their policies connected issues ranging from whether schools would disclose to parents arsenic soon arsenic a pupil 'comes out' arsenic transgender oregon questions their gender, to whether children should play successful sports teams that don't lucifer their enactment registered astatine birth. Only 154 of 304 schools responded. Not each of the schools responded to each of the questions asked.
The study claimed immoderate schools felt disclosing accusation to parents astir whether a questioned their sex identity, oregon expressed a privation to alteration gender, would breach the child's confidentiality.
When asked astir the study during a sojourn to the UK Atomic Energy Authority successful Oxfordshire connected Thursday, Mr Sunak said helium was "very concerned."
He added: "For me, the information and wellbeing of our children is of paramount importance. I've besides been wide that parents indispensable beryllium capable to cognize what is being taught to their kids successful school, particularly connected these delicate areas.
"I'm besides going to accidental contiguous that for the summertime word we volition marque definite we people guidance for schools truthful that they cognize however to respond erstwhile children are asking astir their gender.
"These are truly delicate areas, it's important that we dainty them sensitively, and that parents cognize what's going on, and we'll marque definite that that happens."
The Teaching Union Association of School and College Leaders said schools had been waiting for guidance for "several years."
ASCL General Secretary Geoff Barton said: "Schools enactment precise hard to beryllium delicate to the needs of pupils questioning their sex identity, and each their pupils, by providing a supportive and caring environment, and teaching children sensitively astir respectful relationships successful a divers nine done RSE lessons.
"Unfortunately, they are endeavouring to bash this successful the discourse of a nationalist minefield of powerfully held and opposing views, of which this study from a think-tank is yet different example.
"Meanwhile, the authorities has inactive not produced guidance for schools connected supporting pupils who place arsenic trans oregon who are questioning their sex identity, contempt this having been nether treatment for respective years.
"This is intelligibly needed truthful that schools are capable to gully connected an established acceptable of guidelines alternatively than perpetually being caught successful the crossfire betwixt opposing views and beliefs."
A Department for Education spokesperson said its precedence was the information and wellbeing of children and young people.
"The acquisition caput is moving intimately with the curate for women and equalities to nutrient guidance for schools, which we volition beryllium consulting connected shortly.
"In the meantime, we are wide that schools should marque definite they enactment with parents, pupils and nationalist services to determine what is champion for idiosyncratic children."