In humans, a gamete contains 23 chromosomes. This is half the number of chromosomes found in most body cells, which have 46 chromosomes. The reason gametes have half the number of chromosomes is due to a process called meiosis. During meiosis, the number of chromosomes is reduced by half to ensure that when two gametes (sperm and egg) combine during fertilization, the resulting zygote will have the correct number of chromosomes, which is 46.
Each gamete carries one set of chromosomes, and when they fuse, they form a complete set of 46 chromosomes, with 23 coming from each parent. This ensures genetic diversity and the correct number of chromosomes in the offspring.