* Sperm: Male gametes, produced in the testes. They are small, motile cells with a flagellum (tail) that allows them to swim towards the egg.

* Egg (ovum): Female gametes, produced in the ovaries. They are large, non-motile cells that contain a significant amount of cytoplasm and nutrients.

Both sperm and egg cells are haploid, meaning they contain only half the number of chromosomes (23) found in a normal human cell (which is diploid, with 46 chromosomes). This is crucial for sexual reproduction, as the fusion of a sperm and egg during fertilization results in a diploid zygote with the full complement of 46 chromosomes.