Are you playing v1.0 or v1.1?

I got that when I played v1.0 with the Village Sim Editor. It happens when I altered the gender of the kids born because my women were all dying out. So eventhough their status and name are females but when they grow up, they will still look like males. And they made funny female sound when you drag them around - pretty weird. So I stopped giving them sex change. Hahahaha!