Here's why:

* Human somatic cells (body cells) have 46 chromosomes (23 pairs). These chromosomes are arranged in pairs, one chromosome from each parent.

* Gametes (sperm and egg cells) are haploid, meaning they have half the number of chromosomes as somatic cells. This is because during fertilization, a sperm cell (23 chromosomes) fuses with an egg cell (23 chromosomes) to create a zygote with 46 chromosomes.