Someone who practices Christianity as a religion and believes in the teachings of Jesus Christ is called a Christian. A short Christian is any Christian who has a short height and a small frame. Stature or height is all in the genes. Generally, a short Christian belongs to a family in which people are mostly short. Stature is never the criteria to judge any person. A short Christian can be much more influential and successful than a tall Christian.
There are people who form opinions about short Christians just because they stand short and don't have much of a height. But the true worth of a person is not determined by his physical traits. A charming personality often gives you those extra points when it comes to winning people's hearts and creating an impression and a tall stature certainly accentuates your looks. But this does not imply that you can rule out a short Christian just because of his stature.