Colin Begg of New York’s Memorial Sloan-Kettering Cancer Center argues that genetic susceptibility is nowhere near as clear cut as many geneticists would like to believe and that there are many environmental and lifestyle factors which reinforce or protect against it.

Colin reviewed many studies of breast cancer risk in women with two common breast cell mutations, BRCA1 and BRCA2. He established that the studies which had taken such subjects from families with histories of breast cancer calculated far higher levels of risk (sometimes as high as 85% - almost certainty!) than the studies which had included women whatever their family history. These produced a much lower and consistent risk, thus probably more correct.