What is female gender of horse?

It all depends on what you will be doing with the horse and the nature of the horse. There are many different opinions in the horse world. There are good natured mares (female horse) that can suit your needs as well as a gelding (male horse). Mares can get hormonal, just as women. Some geldings can still get feisty around a mare if she is in season. If you are a beginner or first time horse owner a good, solid, seasoned horse regardless of sex is what you need. If you are going to show some swear by mares saying they are more gritty. Some swear by a steady gelding and can do w/o the estrogen. It's all in who you ask and what you need.