Scarlett Johansson and Ryan Reynolds are desperate to start a family. They are reportedly keen to have a child as soon as possible, and are already discussing the best time for Scarlett to conceive.

A source told the Chicago Sun Times newspaper: "Scarlett and Ryan are madly in love and want to start a family sooner rather than later. Scarlett is keen to be a young mom and does not plan to be the sort of women who leaves motherhood too late and starts worrying about her biological clock ticking."

The 23-year-old actress - who recently completed filming her new movie 'He's Not That Into You' - isn't due to start working on her next project 'Amazon' until late next year, prompting speculation now could be the perfect time for her to get pregnant.

Scarlett is keen to be a young mom and does not plan to be the sort of women who leaves motherhood too late and starts worrying about her biological clock ticking.

The pair are also said to be contemplating adopting a child from an American inner city.