What percentage of regular seeds will be female?

It is usually best to assume a female/male ratio of 50:50. Therefore, germinate twice as many seeds as you intend to grow. In practice, the natural female/male ratio is more like 65:35. This is because cannabis spreads its pollen through the air, without the need for pollinating insects, and therefore requires fewer males than females.
Particularly difficult (low temperature and humidity) or stressful conditions during the early part of a plant’s life may marginally increase the chance of that plant becoming male or hermaphrodite