The ultimate goal of the sperm is to fertilize the egg.

• However, to meet the egg cell, the sperm must go through a long and tedious path.
• After ejaculation, once inside the woman’s body, sperms have to overcome a great number of obstacles that will make it difficult for them to get to the Fallopian tubes and fertilise the egg.
• The distance a sperm has to travel is about 15 cm, and it is in fact a race against time.
• The lifespan of an egg is on average about 24 hours.
• Sperms can survive for up to 2-5 days once inside the female reproductive tract.
• Following ejaculation, the sperms begin a race where not only speed is crucial, but also resistance.
• Sperms with defects and/or poor motility will not make it to the end.
• Some of the obstacles the sperms will encounter include:
• Vaginal pH – Not every sperm cell is able to survive inside the vagina due to the acidic pH
  Response of the immune system – The woman’s white blood cells detect the sperm cells as “foreign cells” and try to destroy them.
• Cervical mucous – Secretions from the cervix and vaginal discharge vary in consistency and texture throughout the menstrual cycle. During ovulation, cervical fluid is more thinner and less denser to facilitate the passage of sperm. Conversely, when the woman is not ovulating, this fluid becomes denser and viscous, which complicates the sperm’s journey.
  Physical barriers
• The internal anatomy of the female reproductive system (vagina, cervix, uterus, Fallopian tubes) is in itself an obstacle for the sperms.