This surgery took balls!

A Pennsylvania man was getting a vasectomy when a rare earthquake struck the New York City area Friday morning — forcing the surgeon to set down his scalpel as the poor guy wondered whether “a train was passing,” he said.

“The doctor was like, ‘I think this is an earthquake.’ I figured he was messing with me, but he had to stop because everything was shaking,” Justin Allen of Horsham told the Guardian.

“[He] put the tools down for a moment.”

Allen got the shaft timing-wise when the 4.8-magnitude quake began shaking the hospital room right as he was going under the knife — fully lucid with local anesthesia — at around 10:25 a.m., he said.

“I thought maybe a train was passing by,” he said. “We talked about how we’d never forget where we were at that moment.”

But Allen didn’t feel caught with his pants down because the doctor had done such a good job preparing him for the surgery, he said.

“I really wasn’t worried because he had walked me through every step of the procedure, so it mostly felt like a brief speed bump and we were mostly just calm and laughing as the room shook,” he said.

After the psyche-rattling experience, he was on the mend Friday.

“Everything turned out great. I feel about as good as I possibly can as the numbing is starting to wear off,” said Allen, who also fired off a viral tweet about the surgery.

Meanwhile, his wife, Bridget, called it a sign from God that their baby-making is over.

“We should never ever ever have another child ever again … ever,” she quipped on X.

The frightening earthquake struck near Lebanon, NJ — roughly 40 miles from Horsham — around 10:23 a.m. It was the first time a major tremor hit the city and tri-state area since 2011, according to the US Geological Survey.

It wasn’t clear Friday where Allen’s surgery took place. He didn’t immediately return a call from The Post.