The Ugly Betty star, who gave birth to daughters Dolly and Charlie with husband Jerry O'Connell in January, said that she is surprised at how boisterous their fighting can be.
She told chatshow host Ellen DeGeneres: "I had this fantasy that when I would have two little girls they'd be wearing matching outfits with little bows in their hair. But these girls wrestle, and whatever I put in their hair they pull out and it goes directly in their mouth."
Romijn continued: "Whatever babies shouldn't do, they do. If I have a sweatshirt on with the cord in the hood, they pull it out and try to wrap it around their necks. I'm like, 'Nooooo! Don't do that!'"
The 36-year-old actress, who named one of her daughters after singer Dolly Parton, revealed that Parton was thrilled at the honour. She said that when she saw the country singing star, she was "a little bit embarrassed to say it".
She continued: "Dolly said, 'Oh, I would be so honoured. Dolly was the name I was given, it's not short for anything, and I don't have any children of my own. Please do it!'"