: First, what exactly are the wizards? I say exactly, but in all honesty, long detailed answers stating history in middle earth tend to confuse me as my knowledge is strictly what is stated in the Hobbit and The Lord of The Rings.

: Second, why did the wizards have such a long life? Again short and sweet would be greatly appreciated for the same reason as the first.

: Last, did any of the wizards have children either adopted or biological, or at least could they have. All I know is what I have read so far, so I am grateful for your replies.

: With love to all who may read this,
: Dulcinea

Rob Roy gives very good and concise answers to your questions. However, it occurs to me that you might need a little more background. Please forgive me if any of this is redundant.

At the beginning of time, Eru [roughly analogous to the Christian God] created Arda. A number of spirits entered Arda to fulfill a vision shown them by Eru. The fifteen greatest of these spirits were known as the Valar. The Valar were transcendant beings and can be visualized as similar to the Roman or Greek pantheon. [I know this is an imperfect comparison]
The strongest of the Valar, Melkor, became Morgoth-the first great enemy. Sauron was his servant. The great wars of the First Age alluded to in LOTR and TH concerned wars against Morgoth. Eventually, Morgoth was defeated by the other Valar and cast into the Void. This titanic war destroyed and sank a large portion of Middle Earth. Afterwards, the Valar refused to intervene directly in the affairs of Middle Earth.

The Maiar were spirits similar to the Valar, but more numerous and lessar in stature. As Sauron's power grew, the Valar sent five emmisarries to oppose him. These were the Istari, who were known as Wizards among Men. These emmisarries were clothed in the shape of Men, and were forbidden to seek to rule or to oppose Sauron by direct force.