Donald Trump 'Apprentice' Contestants Were Tested For STDs, New Book Claims

Contestants on Donald Trump's old NBC reality show, "The Apprentice," were tested many, many ways before being fired ... and one test allegedly involved their genitals.

Trump's TV apprentices were subjected to STD testing ... according to a new book, "Apprentice in Wonderland: How Donald Trump and Mark Burnett Took America Through the Looking Glass," written by Variety Co-Editor-in-Chief Ramin Setoodeh.

Per Ramin, Trump wasn't the one concerned with contestants having sex on set ... the guy behind the STD testing was apparently Mark Burnett, the show's producer.

Former contestant Bowie Hogg, an 'Apprentice' in the first season, claims the STD tests during his season included a funnel being inserted into his penis.

In an excerpt from the book, Hogg says ... "They turned it and scraped it and pulled it out. And it was the most painful thing I've experienced in my whole life."

As for why Trump's producer allegedly wanted contestants tested for STDs ... Setoodeh claims Mark was covering his bases so he wouldn't be held legally liable for "anything that was shared after the boardroom closed for the night."