The 41-year-old actress - who already has a five-year-old son, Henry, from her relationship with director Darren Aronofsky - hasn't ruled out the possibility of extending her family with her James Bond star spouse.
She told Lucky magazine: "Oh, I wouldn't make [a baby] just for the sake of giving my son a sibling. But ... You never know."
Daniel, 43, already has a 19-year-old daughter with his ex-wife, actress Fiona Loudon.
In the interview, Rachel also revealed that acting wasn't her first choice profession when she was growing up.
Rather than grace the silver screen, the Oscar winner wanted to be a police detective or a prehistoric fossil-hunting palaeontologist.
She explained: "I wanted actually wanted to be a detective, and a palaeontologist. I was really into fossils. Though perhaps I was just trying to impress adults by saying that I knew that word."
Rachel and Daniel - who star together in upcoming horror movie 'Dream House', which was filmed throughout 2010 and is due to be released in September - married in a low-key service attended by just four people in June.