[Family background. Parity. Breast feeding and cancer of the breast]. / Antecedentes familiares. Paridad. Lactancia y cáncer de mama.

A study has been carried out of case-controls in a population of 482 women aged between 40 and 98. Of these, 194 had been diagnosed with breast cancer by means of a biopsy and the remaining 288 were controls whose lack of tumoral processes had been ensured by the usual diagnostic means. In the population under study we have found that the maternal family background in the first degree was a risk factor for breast cancer, while giving birth and breast-feeding, both one's own and one's children, acted as protective factor.