I was watching Gangs of New York on Bravo last night...?

And when Leo DiCaprio and Cameron Diaz are about to get it on for the first time, he takes of her shirt and she has this wierd scar on her stomach...and then she's like "they cut it out when i was a child, sorry" and he's like "it's ok", or something. And then they just don't have . I missed a part of it and i'm really confused. What was she talking about? Who were "they" and what did they "cut out"? Thanks.