This STI is the main reason people are rejected from The Bachelor

US Bachelor cast
The medical testing reveals herpes is more common than any other disease. Photo credit: The Bachelor

A new book has lifted the velvet curtain on the secrets of US reality show The Bachelor, revealing one of the main reasons love-lorn hopefuls aren't allowed on the show.

Los Angeles Times writer Amy Kaufman has penned Bachelor Nation: Inside the World of America's Favorite Guilty Pleasure and reveals that many candidates are turned away because they're carrying herpes.

Candidates are taken for medical examinations, Kaufman reveals, with samples of blood and urine collected and tested for drugs and sexually transmitted infections (STI).

If it turned out the applicant had an STI, they would be out of the running immediately.

And apparently, that's the top reason applicants don't make it onto the show.

An excerpt published by the New York Post reads:

"As soon as the medical tests came back, you'd see that herpes was the biggest thing," said Ben Hatta, [creator and executive producer] Mike Fleiss's old assistant. "And sometimes you'd be the first person to tell a contestant that they had herpes.

"You'd be like, 'Uh, you should call your doctor'. Why? 'We're not going to be able to have you on our show, but you should call your doctor'.

"Then they'd realise they'd been denied from The Bachelor and now a bunch of people knew they had herpes."

Although the process would be highly embarrassing, it probably isn't uncommon. Genital herpes is much rifer than many realise.

In the United States, one-in-six sexually active adults have it - that figure is 30 percent in New Zealand - so it's unsurprising that's the chief disqualifier on this reality show.

Newshub.