A Dutch team found left-handed women were more than twice as likely to develop premenopausal breast cancer as non-left handed women.

The researchers believe the key may be that left-handers are exposed to greater levels of sex hormones testosterone in the womb.

Lesley Walker, of Cancer Research UK, said the study was based on a relatively small sample.

“A much bigger study is required to determine the actual risks of left handedness.

“If the results of this study are borne out, it could highlight a group of pre-menopausal women to whom early screening could be targeted.

This sounds too easy. Why hadn’t anyone noticed a pattern before? If true, however, highly interesting.