1993; Russo et al. 2005). Previous studies investigating the influence of pregnancies on the BC risk in BRCA1/2 mutation carriers have, however, yielded inconsistent results: while some authors reported no association with all or even an increased BC risk, with an elevated risk for each additional pregnancy (Jernstrom et al. 1999; Gronwald et al. 2006), others have described a protective effect and a risk reduction for each additional birth (Andrieu et al. 2006; Antoniou et al. 2006; Milne et al. 2010). The gene discussed is BRCA1; the disease is breast cancer.