Sperm is produced inside of the male’s testicles. They have a limited life span, and they cannot divide. It only takes one sperm cell to fertilise an ovum, and, after fertilisation, the ovum is called a zygote, as new organisms begin developing. Although it only takes one sperm to fertilise an egg, there around 280-400 million sperm cells in each ejaculation. This is because there is such an arduous journey from the vagina to the fallopian tube that only few sperm cells will survive. Even for the sperm who survive that trip, the egg is covered in a thick layer that makes fertilisation very strenuous. Most experts believe that this helps allow the healthiest sperm cell to fertilise the egg, providing the best chance for a healthy baby. To create a healthy baby, there needs to be 46 chromosomes. With the combination of a male sperm cell, which has 23 chromosomes, and the female ovum, which also has 23 chromosomes, this can be achieved. A sperm cell consists of a head, a mid-piece and a tail. The head contains the nucleus, which has chromatin fibers. These contain enzymes used for breaking through to the female egg. The mid-piece has a central core with many mitochondria. This is used for energy for when the sperm is traveling through the female’s body. Lastly, the tail is used to propel the sperm cell. There are two stages to the development of a sperm cell. The first stage takes 70 days to complete in the testicles. This is known as spermatozoon. After this, the second stage known as spermatid occurs. It takes around 60 days and it is when the tail of the sperm is developed. Then, the sperm is fully ready to fertilise an ovum. The sperm cells can only survive within the female reproductive system for five days.To keep sperm count healthy, you need to: avoid smoking, drugs, pesticides and heavy metals, limit alcohol intake, have a healthy diet and body weight and keep your scrotum cool. Unlike women, who stop producing eggs after menopause, men continue creating sperm for the rest of their lives. But, sperm count decreases with age and obesity. Lastly, sperm carry either a ‘X’ or ‘Y’ chromosome, which will determine your baby’s gender. Although male sperm are faster swimmers, female sperm are stronger during the journey to the ovum.