A gamete is a reproductive cell that carries half the genetic information of an organism. In humans and many other organisms, each trait is determined by two alleles, one inherited from each parent. However, each gamete only carries one allele for each trait because during the formation of gametes through meiosis, the alleles segregate so that each gamete receives only one allele from each pair. This is crucial for maintaining genetic diversity and ensuring that offspring receive a combination of traits from both parents.