An Altered Sex Ratio Among Offspring of Male Gastroenterology Fellows Between 1970–2008

Abstract

Purpose: An observation of a tendency towards a lower secondary sex ratio, therefore predominantly female offspring, born to male gastroenterology fellows during their fellowship training at Allegheny General Hospital led to this study aimed at identifying any deviation from sex ratio already established in U.S. population studies. Previous studies have indicated that stress alters the sex hormone levels of the parents, which is related to the sex outcomes of their child. Methods: The study was performed at Allegheny General hospital, Pittsburgh, PA. Full approval of the Institutional Review Board was obtained prior to commencement of the study. All male gastroenterologists who had completed a fellowship at Allegheny General Hospital from 1970 (the inception of the program) to 2008 were invited to participate in the study by means of a questionnaire. The questionnaire included the physician's name, contact information, sex and dates of fellowship training. It also inquired into the gender of all children conceived by them and the dates of their conception. An informed consent was obtained from each of the study participants prior to inclusion in the study. Data was collected from the above questionnaires including the total number of children born during this time period and divided into 2 groups: the number of children conceived during fellowship training and those conceived out of fellowship training with the number of male and female children being calculated in each group. A sex ratio (ratio of males to females) was determined for both groups and compared with a control sex ratio. The control sex ratio was based on data from U.S. census reports from 1970–2005 and determined to be 1.050. Results: A total of 74 fellows were invited to participate; 45 fellows responded and were included in the final data analysis. A total of 94 children were born in the study period. Total children conceived in fellowship were 26 (9 male and 17 female with a sex ratio of 0.529) and 68 (34 male and 34 female with a sex ratio of 1.000) were conceived out of fellowship. This difference between the sex ratio of children conceived during fellowship and that of children conceived out of fellowship as well as the control sex ratio approached clinical significance (with a 95% confidence interval of 0.443–0.8279) but was not statistically significant. Conclusion: Our data indicate a trend towards an altered sex ratio for the offspring of male gastroenterology fellows but our results did not reach statistical significance. It is not clear from our study if this trend is indeed due to increased stress of fellowship training resulting in altered sex hormone levels. Further studies may be needed with larger number of subjects to look into this interesting association.