The hardest-working man in the insemination business is at it again this Father’s Day, doing what he does best: impregnating strangers. But now an entire nation is trying to stop him.

“They’re banning my sperm,” Ari Nagel said of Israel’s Ministry of Health.

Known as the Sperminator, Nagel, 42, has fathered 33 children over the past 10 years, many of them born to New York women after he ejaculated into cups in public restrooms — including at a Brooklyn Target and a Starbucks.

In December, a 43-year-old woman agreed to fly the Seed Superman to Israel with the intention of freezing his sperm at a private clinic. But before he even left the clinic, Nagel said, an employee disposed of his sample and told him the facility was not allowed to store his sperm. He believes the clinic recognized his name and alerted health authorities, which ordered the move.

The Ministry of Health sent a letter to the would-be mother saying Nagel’s sperm cannot be used in Israel and that all sperm banks have been alerted.

According to Israeli law, sperm donation must be anonymous; neither the donor nor recipient can know one another’s identity. Nagel, the letter suggests, is widely known. Knowing Nagel’s identity and wanting him in their children’s lives, the mothers have said, is the very reason he is in such high demand in the country.

An exception to the law is made when the donating male signs a documents saying he will co-parent with the mother. Nagel — who’s married with three children ages 4, 7 and 14 — signed such a document with the woman, along with six other would-be moms who have also frozen his sperm in Israel.

That sperm, including some stored at Assaf Harofeh Medical Center near Tel Aviv, has not been destroyed. But those women, who have prepaid for annual storage at nearly $1,400 a year, are also not allowed to ­retrieve it.

The Ministry of Health refuses to recognize Nagel’s fatherhood pledge. According to a letter sent to another would-be mother, “considering the number of women whom Mr. Nagel impregnated with his sperm . . . it is our position that the claim of an intention to perform true joint parenthood with Mr. Nagel is not sincere or reasonable.”

The 43-year-old woman decided to fight back, suing the Ministry of Health for the right to use Nagel’s sperm. The case has been kicked up to Israel’s highest court.

The hopeful mom declined to speak with The Post. Her name is confidential in court papers.

The controversy has left Nagel flummoxed. “There’s a do-not-donate list, and I’m the only one on the list,” he said.

As for the six Israeli women — all of whom are in their early 40s — who have had to put motherhood on hold because of the ban, “They cry to me all the time.”

Nagel believes that Israel hastily changed its laws to prevent him from being a legal sperm donor, he said, based on the findings of the 43-year-old woman’s lawyer.

The Post reported in June 2016 that the New York State Health Department ordered Nagel to obtain a license for donating his seed. He has yet to comply.

Seven new bundles of joy were born of his fruits in the past year — from The Bronx, Long Island, Harlem, Maryland, Orlando, Fla., and Staten Island — some receiving takes on Nagel’s first name, including Aries and Chari. Another 10 babies are on the way.

Nagel’s been fielding requests from women all over the globe. “I have a lot of clients in England,” he said.

Earlier this year, Nagel met a potential baby mama — and her mother — in Midtown.

“I like when they show up with the moms,” he said. “It means they’re family-oriented.”

The younger woman conceived baby Cali, born last month, in an Argo Tea shop that day, via his usual restroom-cup method.

Nagel, a CUNY math professor, has also been asked to be a guest lecturer in a local academic’s genetics class, and recently learned he was the subject of a sociology lesson at NYU.