The best way to check for breast cancer (technically called as screening) is to test for abnormal "BRCA" gene. But it is costly and not easily available commercially. So the alternative approach is to get a mammogram(breast xray) test done annually once to look for development of any abnormality. There is higher chance of getting breast cancer only if two of your close relatives (siblings/mother/aunt) have such cancer. Generally, a mother diagnosed of breast cancer doesnt pose a risk of cancer in her children in 90% of the cases. So rest assured in them.