Shouldn't we have 4 genes to a given character?

Each chromosome has only one copy of a gene. Each gene contains one allele for a given trait. This means you have one copy from your mother and one from your father. When cell division is occurring and therefore the chromosomes replicating, you will momentarily have 4 copies of that gene, but the sister chromatid of each logous chromosome divides into the new cell. I don't think I explained that very well but basically, there are only two genes (two copies of the same gene) for each characteristic.