The human cells that never have 23 pairs of chromosomes are gametes, also known as sex cells. These are the sperm cells in males and egg cells in females.

Here's why:

* Diploid vs. Haploid: Normal human cells (somatic cells) are diploid, meaning they have two sets of chromosomes (23 pairs), one from each parent. Gametes are haploid, meaning they have only one set of chromosomes (23 total).

* Meiosis: Gametes are produced through a special type of cell division called meiosis. Meiosis involves two rounds of cell division, reducing the number of chromosomes in the parent cell by half. This ensures that when a sperm and egg cell combine during fertilization, the resulting zygote will have the correct number of chromosomes (23 pairs).

Therefore, only sperm and egg cells have 23 chromosomes, not 23 pairs.