When my khakis were about 3 weeks old I looked at their vent and by all viewing they look to be female. As they have grown in different stages I check all over the internet and especially this site to see ducks that look like mine at different ages. So far, it looks as if I have female Khakis. They are about 11 weeks now and are loosing feathers, but all markings, color, beak, seem to say female. Do some searches and look at pictures. I don't know that I will be positive until I see eggs!!