The 22-year-old singer - who has been dating baseball star Matt Kemp since January - has a list of ambitions she wants to achieve before becoming a mother, but has not given herself a definite time deadline to start a family.
She said: "I don`t really plan on the age. It could be a year from now. It could be 10 years from now. Whenever is right.
"I mean, I have a lot of other stuff to accomplish before I get to kids. Whenever the time is right, I`ll just know."
While Rihanna is unsure when she will have a baby, she knows she would prefer to have a son.
She explained in the December issue of Interview magazine: "If I had a girl, she`d probably be really rebellious. She would be like a bundle of karma."
The `Only Girl in the World` hitmaker also would "love to" raise a family in her native Barbados but doesn`t think it would be possible because of her pop career.
She explained: "I can`t live that far away from everything now, without kids. So I certainly couldn`t raise kids and have a career with the demanding schedule that I have."