Question about Mules?

Question

A Mare (Female Horse) + A Jack (Male Donkey) = a Mule

Why can't a Female donkey(Jenny) and a Male Horse (Stallion) have a mule?

Answer 1

because of some thing in the bible

Answer 2

Progeny of a stallion and a jenny (female donkey), are more horselike in appearance than a mule.

It is called a hinny, although the female is commonly known as a molly.

Answer 3

They are called a hinny. Hinnies are difficult to obtain because of the difference in the number of chromosomes between the horse and the donkey. http://en.wikipedia.org/wiki/Hinny

Answer 4

When animals are crossbred, the female should be the larger animal and the male the smaller, because genetically, the offspring may be too large for a smaller breed mother to give birth to.  

Another example of this is "kindergoats", which is a pygmy crossed with a Nubian.  You have to use a pygmy buck, because a pygmy doe would never be able to deliver and it would probably kill her.

The mule offspring is always sterile and cannot be bred.