Scientists claim that the 'grandmother effect' could help explain why breast cancer is not passed on more frequently.
It has long been understood that women with the breast cancer gene are around 50 per cent more fertile than those without it.
This suggests that rates of breast cancer should increase along with the number of offspring, when they have remained relatively low.
Dr Jack da Silva, from the University of Adelaide's School of Molecular & Biomedical Science, said that the grandmother effect could explain this anomaly.
He said that post-menopausal women that live a long time are more able to support daughters and granddaughters, creating an environment where more grandchildren are born.
However, the reverse is true for women who die young and therefore cannot provide the support for their children.
Dr da Silva said that further investigations are needs to clarify this link and determine why the increase in fertility exists.
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