Girl or Boy?

Here's how i teach N the difference between 'girl' and 'boy. I cut out pictures from a book, laminate them and had N to sort them according to their gender. Sometimes i would take out the Mandarin words cards and have him place the pictures onto the correct word card. N can get confuse (because some of the girl pictures have short hair and some men seemingly wear skirts in their national costume) and sometimes mix them 2 gender up.