How to show a list of only one category

i have categories and sub-categories…. for example

category 1
sub-category 1
sub-category 2
sub-category 3
category 2
sub-category 1b
sub-category 2b
sub-category 3b

when i write the code
<?php wp_list_cats('sort_column=name'); ?>

it shows all of my categories like this:
category 1
sub-category 1
sub-category 2
sub-category 3
category 2
sub-category 1b
sub-category 2b
sub-category 3b

but I only want to show the sub-categories of category 1:

sub-category 1b
sub-category 2b
sub-category 3b

is it possible?

thank yous o much