Purpose:To find whether having children in medical school affect time to speciality, also when controlled for age, gender and life events. We also wanted to find out if having two or more children would impact on time to speciality. Subjects: This study consists of two nationwide 15-year prospective cohorts with 466 respondents from all medical students graduating in 1993, 1994, 1999 and 2000 at all of the Norwegian medical faculties. We followed the subjects with comprehensive postal questionaries at five observations points. Methods: Our outcome variable was length of postgraduate training. We used the following independent variables: age, gender, number of children during medical school, number of children during postgraduate training, life events, place of study and field of speciality. Results: The following variables showed a significant effect on time to speciality; having children during medical school, having children during postgraduate training, gender and life events. Age and having several children during medical school did not have an impact on time to speciality. Conclusion: We found that having children during medical school does prolong time to specialization when compared to not have any children at all. Having several children does not prolong time to specialization when compared to having none or one child. An unexpected findig where that women spent longer time on postgraduate training, even when controlled for having children. This finding needs further studies.