BREAST cancer in men is so rare that little research has been carried out into the factors involved, even though the effects of the disease can be just as devastating as they are for women.

A study of 227 sufferers, thought to be the largest ever undertaken, and published in the American Journal of Epidemiology, found that the risk increases with inflammation of and injury to the testicles, as well as late puberty and infertility. Other risk factors include high cholesterol levels and a history of obesity.

The risk decreases in direct proportion to the number of children fathered. The study concludes that 'adequate testicular function' has a protective role against breast cancer.