This is such an old story.

Long before Mei Xiang came under intense pressure to give us a precious panda cub, there was Anne Boleyn and Marie Antoinette and each of the 14 wives of Mutlaq Sulaiman, a 53-year-old Saudi who discards women like used plastic bags when they don’t produce an heir.

It’s always the same in these high-profile matchups. Everyone’s looking at the female, throwing around words like “barren,” when the problem is at the Y-chromosome end of the process.

And in the world of arranged breeding, international diplomacy and big dollars that is global zoo politics today, the Panda Situation in the nation’s capital was reaching crisis level.

U.S. officials made no secret about plans to deport the furry behinds of Washington’s royal panda couple because of their seeming infertility — they are like the Redskins that way, with a few highs, lots of lows and a bizarrely loyal fan base. But Mei Xiang proved her doubters wrong.

Zoo officials weren’t even sure she was pregnant, but on Sunday night, with a slight exertion caught on video, Mei Xiang produced her second cub.

Saved!

Seriously, Mei Xiang’s inept partner, Tian Tian, had better get her “push present” — what some women expect to receive in the hospital upon delivery (diamonds preferred, thank you) — from Tiffany this time around. He was this close to a ticket back to the homeland.

It’s been pretty obvious to the zoo staff that Pop wasn’t up to the job for a while now. This is the second cub for both and also the second one that is the the product of artificial insemination. Tai Shan, a.k.a. Butterstick, was first, in 2005 .

In a Washington Post interview this spring, zoo research scientist Jon Ballou talked about the panda couple’s dry spell, and 14-year-old Tian Tian’s part in it.

“He has proved to be a clueless breeder with flawed technique. Plus, his genes are not that valuable because his father has sired dozens of offspring in the captive population,” Ballou said.

It sounds like the story of many a fumbling scion, unable to live up to a father’s grand legacy and shriveling in his shadow, dabbling in hobbies such as bamboo and afternoon naps while everyone looks to his beautiful wife with brows raised, question marks in their eyes.

It’s a pretty brutal business out there in zoo land, almost as merciless as the English court.

“Genetically, it would be best if we got a whole new pair,” Ballou told The Post in April. “If she’s not going to breed, then she’s genetically dead,” he said.

Harsh.

The truth is, these adorable animals were simply not meant to survive.

They are fertile only one or two days a year and the males in captivity have shown little interest in mating.

Officials at other zoos have admitted using Viagra and “panda porn,” with little success. Last year, the folks at the National Zoo had Tian Tian do a regimen of leg-strengthening exercises, to help his stamina and technique. A personal sex trainer.

How sad.

If the pandas get lucky and produce a cub, they aren’t home-free. The cubs are so small that it’s about the equivalent of a human giving birth to a tree frog. Who can take care of that? The babies can be crushed or suffocated by their huge moms. Washington’s original pair of pandas, Ling-Ling and Hsing-Hsing, produced five cubs during their years at the zoo, but none of their offspring survived beyond a few days.

National Zoo officials inseminated Mei Xiang this year and waited, frustrated by inconclusive ultrasounds. It’s not like she’s uncooperative: Mei Xiang is so used to this obsession of ours that she rolls over whenever she sees the ultrasound and fertility gear, poor thing.

And early this month, she began showing signs of nesting. In human Washington, that usually means lots of crazy shipments from Pottery Barn Kids or Great Beginnings. But in her case, it meant shredding bamboo or cradling an apple.

As far as we know, Tian Tian did nothing.

His “vintage sperm” was taken from the same frozen sample that gave the panda couple a baby in 2005. He didn’t even have to go for the porn.

And then, on Sunday, the folks on duty saw Mei Xiang’s quiet, little miracle.

“She kind of breathes funny and then she jerks her body, and then she stands up and kind of looks at something for just seconds . . . and then picks it up,” marveled Don Moore, associate director for animal-care sciences.

Zoo officials have been hearing squeaks and cries ever since, and are watching Mei Xiang cradle that little bit in her big paws.

Relax, Daddy-O. Go watch the Redskins, or the Nationals or the election. It’s a big year in Washington, and your lady just made sure you’d get to stick around to see it.