Recent analysis has shown that women from some countries had birth ratios different from that of the United Kingdom as a whole; i.e. 100 female births to 105 male births. There are many possible causes of these ratios. The department is carrying out further analysis of related data. We do not consider it is in the public interest to disclose details of the countries in question while this analysis is under way as it is not currently possible to conclude that these variations are the result of intervention rather than natural variation.