Angelina Jolie: Should women be worried by genetics?

Angelina Jolie's decision to have a preventative double mastectomy is expected to raise awareness of breast cancer and the dangers posed by genetic mutations.

But the vast majority of breast cancers are not caused by genetic factors, and are instead linked to behaviours such as smoking and conditions like obesity.

BBC News online health editor Michelle Roberts - herself a qualified doctor - looks at what Angelina Jolie's decision to choose surgery means for other women.