Predictors of survival after lung transplant were analyzed in a large cohort of 990 lung transplanted patients from a single center. The overall survival was 41.6%, (41.5% in males, and 41.8% in females), the average length of the follow up was 45.84+/-51.98 months (range 0-282.47 months). Females tend to live longer than males: 50.75+/-55.41 months versus 40.64+/-47.60 months, respectively. Males had a risk of dying during the follow up that was 1.18 (95% CI 1.01-1.40) relative to females, after adjusting for ethnicity, age, smoking status, diagnosis and donor characteristics. Females who had at least one full term pregnancy during their life had better survival rates than females who had no full term pregnancies. Our results of a better survival after lung transplant in females, and among them in those who had at least a full term pregnancy support the hypothesis of a hormonal contribution to survival and of the development of immunotolerance after pregnancy. This model could be useful for understanding the role of immunity in cancer development.