When I first learned that Mormons thought that God had a body of flesh and bones, I was pretty shocked. But, I soon learned more than that. I read the following from one of Mormonism’s Presidents:
Remember that God, our heavenly Father, was perhaps once a child, and mortal like we ourselves, and rose step by step in the scale of progress, in the school of advancement; has moved forward and overcome, until He has arrived at the point where He now is. “Is this really possible?” Why, my dear friends, how would you like to be governed by a ruler who had not been through all the vicissitudes of life that are common to mortals? If he had not suffered, how could he sympathize with the distress of others? If he himself had not endured the same, how could he sympathize and be touched with the feelings of our infirmities? He could not, unless he himself had passed through the same ordeal, and overcome step by step. If this is the case, it accounts for the reason why we do not see Him—He is too pure a being to show himself to the eyes of mortals; He has overcome, and goes no more out, but He is the temple of my God, and is a pillar there.
– Orson Hyde, Journal of Discourses, Volume 1, Page 123
And from Smith’s successor:
It appears ridiculous to the world, under their darkened and erroneous traditions, that God has once been a finite being; and yet we are not in such close communion with him as many have supposed. He has passed on, and is exalted far beyond what we can now comprehend.
– Brigham Young, Journal of Discourses, Volume 7, Page 333
It seems that the theology of God once being a man is pretty rooted in Mormon doctrine. I thought I should note I got these directly from the Journal of Discourses from a Mormon site.