Twenty million copies of the erotic trilogy “Fifty Shades of Grey”, “Fifty Shades Darker” and “Fifty Shades Free”, have sold in the U.S.  

The books have been mentioned by several celebs, held the top three spots on USA TODAY's Best-Selling Books list for nine weeks, and have even been featured on a "Saturday Night Live" skit.

Sex toys like those described in the book are apparently flying off the shelves, according to some business owners.

“It is absolutely true,” Cheryl Sloane, the co-owner of G boutique in Chicago, said on HLN’s Dr. Drew Tuesday night. “It is amazing to us. Every day, we see all types of women coming in.”

Psychosexual and relationship therapist Simone Bienne added; “What this book is doing, which really, to me, outweighs any negative concerns, is it is getting women in touch with their sexuality.”

However, Dr. Drew said, “I have grave concerns about it. I want the time back I spent reading it, just so you know. I didn't like it. Again, there seems to be one differentiating quality that makes me unable to appreciate the wonders of this book and that is -- I'm a male.”

Listen to full debate in the video player above.

Dr. Drew airs weeknights at 9 p.m. ET. Follow the show on Twitter @DrDrewHLN.