"I think it's definitely up for debate," said Portman. "People are all so different from each other, I'm sure there are people who are capable of it."
The Golden Globe winner also serves as an executive producer for "No Strings Attached." She had promised her mother she'd do something "lighter" after spinning her way into madness on her last film, "Black Swan."
"I delivered. But there is a lot of sex in it, so sorry mom," Portman said.
She's known for being one of Hollywood's most glamorous women on the red carpet. For her character in this film, she got to dress down and wore scrubs most of the time.
"I kept taking photos on my phone and sending it to my dad, because my dad's a doctor and he always wanted me to be a doctor, so I was like, 'Look dad, I made your dream come true,'" said Portman.
The 29-year-old is living the dream right now, enjoying her moment in the awards season spotlight. She says she received a good piece of advice from her "Black Swan" director, Darren Aronofsky, on how to handle all the attention.
"Just have fun with it, and it's true, instead of resisting it and just letting it be fun for what it is and taking it all in. And also allowing yourself to get excited about the people you see, who you admire because you get to be around, at these events, so many people that you respect. That's the real fun of it," said Portman.
"No Strings Attached," rated R, opens in theaters on Friday, Jan. 21.