Three ways to do this:
1. Pivot Tables. I wrote another answer explaining the basics of using them. See the link.
2. SumProduct formula. SumProduct is SumIf on steroids. SumProduct can use multiple criteria, unlike SumIf.
Suppose Gender is in column A and Nationality is in column B. In Cell C1, type in:
=SUMPRODUCT ((A2:A5000="Male")*( B2:B5000="Italian")*1))
and drag down to row 5000
Column C will have a 1 or 0 depending on the results of both comparisons.
NOTES:
Range MUST start in row 2
Both ranges MUST be equal (i.e. 5000)
Ranges can be as large as you need them to be
Do not use too many of these formulas as your calculation time will slow down to a crawl.
3. If calculation is too slow, do a similar comparison with formulas that are not loaded into memory (like SumProduct) if your comparisons are simple.
To find British females,
=if(and(A1="Female", B1="British"),1,0)
To find British and Italian females, things get a bit more complex
=if(or(and(A1="Female",B1="British"), and(A1="Female", B1="Italian")),1,0)
The second formula basically has two AND functions nested insise an OR function.
Hmmm...now that I think of it, you could rewrite it as:
=IF(AND(A1="Female", OR(B1="British",B1="Italian")),1,0)
Hope this helps. Send me an email if you need more help.