Recent studies have suggested that variance in age of onset strongly influences selection of alleles involved in susceptibility to late-onset diseases that would lead to rapid death of carriers in the absence of modern medicine (e.g. breast cancer in BRCA1 carriers) and that, therefore, alleles under negative selection small enough to be traded-off for a positive effect at younger ages (e.g. BRCA1) may be more strongly negatively selected that thought [79]. This evidence concerns the gene BRCA1 and breast cancer.