Some women may inherit a predisposition to breast cancer and some may inherit an as-yet unidentified protective factor. However, surveys and studies suggest that there are factors aside from genetics that seem to influence whether a woman will develop breast cancer:

* In general, women who bear children have less risk of breast cancer than women who are childless.

* Women who bear children before the age of 18 appear to have added protection against breast cancer.

* But women who bear their first children after age 35 have a greater risk of developing breast cancer even than childless women.

* Breast-feeding, once thought to confer a protective factor, is not now believed to influence cancer incidence. However, some European studies suggest that a woman may be protected during the actual period she is breast-feeding.

* Others considered to be more at risk: overweight women, Jewish women of European extraction.

* Studies are under way to determine if high-fat diets, and diets deficient in C and B-complex vitamins and in selenium, are linked to a higher incidence of breast cancer. (Selenium is a trace metal found in seafoods, liver, whole grains and vegetables like cabbage.)

For all women, periodic examinations and mammograms, according to a schedule your physician suggests, should be augmented by monthly self-examination. Early detection may not guarantee a cure, but it may minimize the necessary treatment.