The dual aims of this study were: to assess the effect of being a carrier of a germ-line BRCA1 or BRCA2 mutation on the risk of spontaneous abortion; and to investigate whether or not there is an association between spontaneous or therapeutic abortions and the risk of breast cancer in women with a BRCA1 or BRCA2 mutation. This evidence concerns the gene BRCA1 and breast carcinoma.