Problem to show empty row

Morning all,
I am trying to generate a report using cross tab feature.
I must show for each country the number of detected people divided by gender. Unfortunally I have one problem, some gender rows are empty becouse doesn't exist detected people, and when I try to generate report it is wrong with value position wrong. I need to know a method to show value zero (0) when the row is empty.
An example is

_________________________
| country | Male | Female |
-----------------------------
| Albania | 10 | 0 |
-----------------------------
| Italia | 2 | 5 |
-----------------------------
and go on.

Thanks to all :)