Cells that contain only one set of chromosomes are known as haploid cells. These cells have half the number of chromosomes typically found in diploid cells, which contain two sets of chromosomes, one from each parent. In humans and many other organisms, haploid cells are primarily represented by gametes: sperm cells in males and egg cells in females.
The process of meiosis is responsible for producing haploid cells. During meiosis, a diploid cell undergoes two rounds of cell division, resulting in four haploid daughter cells. This is essential for sexual reproduction because when a sperm cell fertilizes an egg cell, the resulting zygote restores the diploid number of chromosomes, ensuring genetic diversity in the offspring.