Reproductive cells

The eggs and sperm are the reproductive cells. Each mature reproductive cell is haploid in that it has a single set of 23 chromosomes containing half the usual DNA amount.

Except for the eggs and sperm, each cell in the human body — there are 100 trillion cells in each of us — contains the entire human genome, all the genetic information necessary to build a human being, and this information is encoded within the cell nucleus in 6 billion base pairs, subunits of DNA, packaged in 23 pairs of chromosomes, one chromosome in each pair coming from each parent.

The reproductive cells — the eggs and sperm — are thus notable exceptions to the usual rules concerning chromosomes, genes, and DNA.