Sex and Height
Some mares, however, seem totally unaffected by this and show no change in attitude. In general, a gelding is less likely to be temperamental than a mare. However, in the end, buying a horse is based on common sense.
Never consider buying a stallion. Mares can become temperamental during the spring and summer months when they will come into season at regular intervals.
Once you find a horse that is ideal for you, it really should make no difference whether it is a mare or a gelding.
You need to look for a horse that you are not going to outgrow in a few months, but also one that is not too big for you.