Human cells typically have how many copies of each gene?

The story behind the answer

2. Human somatic cells are diploid, meaning they carry two sets of chromosomes—23 pairs, for a total of 46. Each pair includes one chromosome from your mother and one from your father, so most genes exist as two copies (alleles), enabling dominance/recessiveness and genetic diversity.

Remember: “di-ploid = two.” Exceptions include haploid gametes (sperm and egg) with one copy, X-linked genes in males (one X and one Y, so many X genes are single-copy/hemizygous), mitochondrial genes (multiple copies per cell), and occasional copy-number variations. But in typical body cells, two copies per gene is the rule.