Egg cells, or ova, are the female reproductive cells in many organisms, including humans. They are produced in the ovaries and play a crucial role in reproduction. Each egg cell contains half the genetic material needed to form a new individual, making it essential for fertilization when combined with a sperm cell. In humans, a woman is born with a finite number of egg cells, which decrease in quantity and quality as she ages. During the menstrual cycle, typically one egg matures and is released during ovulation, while the others undergo a process called atresia, where they are reabsorbed by the body.