More than 3.2 million US public school students are covered by guidance that blocks parents from knowing whether their child identifies as a different gender in the classroom — which could become federal policy if President Biden’s Title IX proposals are approved in May.

At least 168 districts governing 5,904 schools nationwide have rules on the books that prevent faculty and staff from disclosing to parents a student’s gender status without that student’s permission, according to a list compiled by the conservative group Parents Defending Education and shared with The Post.

The 3,268,752 students affected by such policies go to class in all kinds of districts — large and small, affluent and poor, urban and rural, red and blue — stretching from North Carolina to Alaska.

The non-comprehensive list includes two of the largest school districts in the country, Chicago Public Schools and Los Angeles Unified School District — along with other city jurisdictions like DC Public Schools, Baltimore City Public Schools, San Francisco Unified School District, Portland Public Schools, and Seattle Public Schools.

Districts from deep-blue university towns — Berkeley and Palo Alto, Calif.; New Haven, Conn.; Iowa City, Iowa; Ann Arbor, Mich.; Hanover, NH; Durham, NC; and Madison, Wis. — appear on the list, as do 11 districts in deep-red Idaho, 16 in purple Pennsylvania and seven in Virginia, where Republican Glenn Youngkin was elected in 2021 in part on a platform of giving parents a bigger say in their children’s education.

Three New York school districts appear on the list — Buffalo City; Brighton, outside Rochester; and Lake George in the Adirondacks.

Nine districts on the list are located in New Jersey — including Fairview, Garfield and Tenafly in Bergen County.

Nicole Neily, president of Parents Defending Education, told The Post the list “only begins to scratch the surface of what is taking place behind closed doors in America’s schools.”

“This investigation shows that parental exclusion policies are a problem from coast-to-coast — and that living in a red state doesn’t mean that families are automatically shielded from this issue,” Neily said.

“Without a doubt, there are hundreds (if not thousands) of others with similar policies on the books. We urge everyone to keep an eye out — and to let us know if they find something similar in their backyard.”

“These policies are everywhere, and not always written down,” agreed Luke Berg of the Wisconsin Institute for Law and Liberty.

“I don’t have a list anywhere near as comprehensive as PDE, but given what I’ve heard from parents, I would assume it is even more widespread than the 6,000 they have documented.”

“In our view,” Berg added, “all of these policies violate parents’ constitutional rights under the United States Constitution, and possibly many state constitutions as well.”

Broyles is currently representing whistleblower Jamie Reed, the 42-year-old former case manager at Washington University Transgender Center in St. Louis.

Reed told The Free Press in February that the gender clinic performed “morally and medically appalling” procedures on children, at times without the informed consent of parents.

The proportion of youth who identify as transgender has doubled — from 0.7% to 1.4% — since 2017, according to reports from the Williams Institute at the UCLA School of Law.

The fight over so-called “parents’ rights” in school transgender issues made national headlines during Youngkin’s gubernatorial campaign after a self-described “nonbinary” teenager sexually assaulted two teenage girls in high school bathrooms in ritzy Loudoun County.

During his first year in office, Youngkin, 56, set about rolling back policies set in place by his predecessor, Democrat Ralph Northam — including allowing students to use bathrooms or play on sports teams that conflict with their biological sex.

“This is not controversial,” Youngkin said in October on CNN. “​The previous administration had had a policy that excluded parents and, in fact, particularly didn’t require the involvement of parents​.

​”If parents actually want their child to be able to change a pronoun or their name or use a bathroom, if parents choose that, then, legally, that’s what the schools will do​.”

Youngkin’s office did not immediately respond to a request for comment by The Post.