Hi Garrett,
While inserting the Column is the easy part, the difficult part (for this report) is to calculate the number of Men and Women for each row.
That's because, the Calculated Members are usually (and almost always) inserted to calculate value by accessing other values on the same row or other row in the Crosstab. E.g: A new column to find out the difference between two age-ranges in the same crosstab etc.
Since there isn't a way to find out how much of those numbers are contributed by men or women, you would need some help from the database.
If that's not possible, the other workaround is to build a Manual Crosstab, however this has its own limitations. A Manual Crosstab requires that you know the number of columns (in this case age-range).
Another way would be to use a Subreport. The Subreport can hold another copy of the Crosstab with just the contributions and the Total Column. Then, with some effort on the formatting, you could probably make it look like one single crosstab.
-Abhilash