Del. Robert G. Marshall (R-Prince William) holds up a history of debates on constitutional amendments in 2014. (Bob Brown/AP)

Apparently, Virginia has its very own “Minister of Private Parts.”

His name is Del. Robert G. Marshall (R-Prince William), and the residents of his district keep electing him to keep talking about other people’s nether regions.

I’m not exaggerating here.

Marshall’s legislative record reads like a conversation between my 10-year-old son and his friends. It’s all potty this and p---y that. (Okay, my 10-year-old doesn’t say p---y, but the president-elect does.)

It’s hard to believe that Marshall is a 72-year-old man. He has devoted much of his public life to people’s sexual and reproductive behavior, questioning the intelligence of women who use long-term contraception, arguing that some incest is voluntary, pushing for women to be legally required to have transvaginal ultrasounds before abortions, worrying that U.S. troops would catch sexually transmitted diseases if they had to serve alongside gay colleagues, calling porn a public health hazard.

And this is from a guy who identifies with the party of small government. So much for personal freedom.

Just in time for the new year and a new session of the General Assembly, Marshall has crawled even deeper into the sewer and unleashed his version of a transgender bathroom bill. It will limit people, kids in school especially, to using the bathrooms of their gender at birth. Because he can’t stop worrying about kids going potty, I guess.

Marshall explained that his bill is based on his fear that men and boys will pretend to be transgender to infiltrate bathrooms and locker rooms used by women and girls.

“Some guys will use anything to make a move on some teenage girls or women,” he said. “Mere separation of the sexes should not be considered discrimination.”

Too much information there, Bob. Because I’m not sure all guys are onboard with your teenage get-the-girl capers.

The Physical Privacy Act, as he ironically calls it, is just like the irrational bathroom bills being considered in other states, which are designed to arbitrate who can use which toilet in schools and other government buildings.

Under this scenario, Marshall — and all the legislators in other states who have pushed this issue, as well as the freaked-out parents who show up at school board meetings — believe that an ill-intentioned guy is willing to go all Mrs. Doubtfire to be able to pee in the stall next to a super-cute cheerleader?

It’s not like that.

A transgender kid usually spends years feeling trapped and confused, trying to figure out the discrepancy between his or her mind and body. If that child is fortunate, his or her gender transition is guided by parents, doctors and psychologists, based on decades of studies and science.

It’s not a “Porky’s” remake, sneaking a peek at the girls’ locker room.

And stigmatizing that transition could be devastating.

This whole psychological blind spot could be solved if Marshall and a few others did a little bit of research and talked to some trans folks.

Heck, one of the most influential transgender women is right in Marshall’s neighborhood. Before Caitlyn Jenner, there was Diane Schroer.

I met her in 2005, right after she left her life as David Schroer, a former Special Forces colonel who had jumped from airplanes, had grueling combat training, commanded hundreds of soldiers and was one of the Pentagon anti-terrorism specialists who regularly briefed Donald H. Rumsfeld and Richard B. Cheney after the 9/11 attacks.

Schroer left the military and was about to take a big job at the Library of Congress. But the library rescinded the job offer after Schroer told them that David would start work as Diane.

Schroer sued and eventually won in federal court, three years later, setting a powerful precedent for transgender folks everywhere.

I double-dog-dare Marshall to try to force Schroer, in her long hair and high heels (and combat training), to use the men’s potty between high-level meetings at defense industry offices.

Gov. Terry McAuliffe (D) has made it clear that he would veto Marshall’s ridiculous bill, if it ever made it to him. It’s not going to even make it that far in Virginia.

And that makes it even more preposterous that Marshall is spending his valuable time and his constituents’ trust to troll the very tiny transgender population in Virginia.

This is that real swamp everyone’s talking about:

Politicians who fixate on their personal obsessions rather than putting their power to work solving real issues in their districts — schools, traffic, unemployment, housing — deserve our scorn.

Try keeping private parts private, Bob. It’s what adults do.

Twitter: @petulad