A haploid cell contains only one complete set of chromosomes, which is half the number found in diploid cells. In humans, for example, haploid cells have 23 chromosomes, while diploid cells have 46. Haploid cells are crucial for sexual reproduction, as they combine during fertilization to form a diploid zygote. In many organisms, including plants and fungi, the haploid stage is part of their life cycle. In plants, the haploid phase is represented by the gametophyte, which produces gametes. In animals, haploid cells are primarily the sperm and egg cells that unite to create a new organism.