It's hard to believe, but "The Bachelor" and "The Bachelorette" actually have exhaustive casting criteria. They don't just let any crazy person on the show, they have to be the right crazy person.

L.A. Times writer Amy Kaufman details the casting process in her new book "Bachelor Nation: Inside the World of America's Favorite Guilty Pleasure." The New York Post shared an excerpt revealing how people get cast, and what keeps them from making it on the show.

First, potential suitors fill out an application and submit photos of themselves. Candidates are then flown to L.A. for final audition weekends. They fill out a 150-question personalty test, have meetings with producers, talk to the show's therapist, go through psychological testing, and allow the show to conduct a thorough background check. (What they find can and will be used against you on camera.)

But you can't get on the show unless you pass the medical examination. As Kaufman writes, samples of blood and urine are collected and tested for drugs and sexually transmitted diseases. Hopefuls fill out their medical history and answer questions about their health. If they have an STD, they are immediately cut. And a lot of them have herpes.

Kaufman revealed that's the top reason applicants don't make it onto the show:

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

Oops. But, as HuffPost noted, genital herpes is pretty common -- "More than 1 in 6 Americans ages 14 to 49 have genital herpes, according to the Centers for Disease Control and Prevention, making its status as the chief disqualifier on a mainstream reality show rather less surprising."

Also less surprising: The psych tests they do don't really weed out the crazies:

"There's psychological tests they have to pass, but there's a window of the pass, do you know what I mean?" insinuated Michael Carroll, the producer who got so close to contestants that he even crashed in their rooms occasionally. "You'd know there'd be a possibility of [someone] being kind of unhinged — like, she passed, but just barely. You can see it at the casting events during the interviews: 'Oh, this chick is going to go ­f–king nuts. She's amazing.'"

If it sounds like Lifetime's "unREAL," it should. That's basically how the show works. The book revealed that one of the show's supervising producers would keep cash on hand to motivate producers to deliver on camera.

"The first producer to get tears? A hundred bucks! You get [the bachelor] to make out with the right girl? A hundred bucks! Catch a chick puking on-camera? A hundred bucks!"

Read more of the book excerpt. Arie's season of "The Bachelor" comes to its own crazy conclusion this Monday and Tuesday at 8 p.m. on ABC. "UnREAL" Season 3 airs Mondays at 10 p.m. on Lifetime.

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