jmc

The socks must be either both white, both brown, or both blue. If the socks are white, there are $\left(\genfrac{}{}{0ex}{}{4}{2}\right)=6$ choices. If the socks are brown, there are $\left(\genfrac{}{}{0ex}{}{4}{2}\right)=6$ choices. If the socks are blue, there is $\left(\genfrac{}{}{0ex}{}{2}{2}\right)=1$ choice. So the total number of choices for socks is $6+6+1=\boxed{13}$.