The sex selection is based on the cancer site that you have selected. Certain cancer sites are sex-specific, for example, statistics for Cervix Uteri cancer are only available for females. When Cervix Uteri is selected as the cancer site, female is the only option available in this menu.
When working on the Statistics by Cancer Site page, selection of sex determines the available options under Select Cancer Site(s). When a cancer site is unavailable the checkbox is disabled.
Sex-specific cancer sites are not available on the Statistics by Sex page.