Your cockatiel has dark grey tail feathers and only two horizontal striped does this mean it is a female?

The presence of dark grey tail feathers and only two horizontal stripes does not necessarily mean that your cockatiel is a female. While these are common characteristics associated with female cockatiels, there can be variations in coloration and markings among individuals. Sex determination in cockatiels is often more accurate through genetic testing or visual examination of the bird's cere (a waxy area above the beak) by an experienced bird keeper. It is advisable to consult with a veterinarian or an expert in cockatiel breeding for accurate sex determination.