Nulliparity is a condition that has been associated with the development of some oncological gynecological diseases. Cancer mortality rates in Catholic nuns (breast, ovarian and uterine) is higher than in general population , and nulliparous women appear more susceptible to these three cancers, as compared to parous women, thus suggesting that pregnancy represents a protected time . It is suggested that in nulliparous women, the increased number of cycles between menarche and menopause expose to an increased risk of hormone-dependent cancers.