How do I show children of a taxonomy term in a block?

I'm using ubercart and there a default vocabulary called catalog.
Right now I have something like this in a block.

catalog
-Women
--dress
--jacket
--pants
--shoes
-Men
--shirt
--suits
--jacket
--pants
--shoes

I added women and men to the primary menu. I would like to show only women and terms under it in a block when someone clicks on it and vice versa for men. How can I do this?

The block would look like this:
-Women
--dress
--jacket
--pants
--shoes

Thanks in advance for all tips.