ggplot2 stacked pyramid by category

Hi,
My data looks like:

school gender n
1 1 200
1 2 230
2 1 60
2 2 215
...

I want to build a stacked pyramid with school at Y axis and n in X axis.
Each step of pyramid should show which part of students is female and which male
Please help

Do you mean like a population pyramid?

If so, this link is a very helpful tutorial on how to make one.

Thank you Mara this is very useful.