Charlize Theron chooses her roles so her son can grow up in a ''better world''.

The 40-year-old actress - who adopted three-year-old Jackson in 2012 - insists she never worries about her projects impacting on family life, but is attracted to parts in ''difficult and socially conscious'' movies because she wants to make a difference.

Asked if motherhood makes her worry about accepting certain parts, she said: ''That's not really an issue for me. I've never been the kind of actor who takes their roles home with them.

''Once I leave the set, that's it. I'm not brooding or sad.

''As a mother, I actually feel more drawn to playing in difficult and socially conscious films so tat my son Jackson can grow up in a better world.''

In the early days of her career, the 'Dark Places' actress struggled financially, but she insists her situation wasn't difficult and most women in Hollywood share the same determined streak.

She told OK! magazine: ''Every actor faces the same situation and I don't consider myself particularly heroic because I wouldn't take no for an answer.

''But I can tell you one thing - that most of the women who succeed in this business are incredibly determined, regardless of how talented or beautiful they may happen to be.''