Fertility facts - Proactive steps

Fertility facts

Making babies is easy right? Take Part A, combine with Part B and the rest, as they say in the classics, happens naturally.

But what about if the “rest” isn’t happening naturally? Or maybe you’re just starting out and you’d like to understand a few of the finer points but you realise that you’ve forgotten most of what you learnt in high school biology about reproduction?

Well, Genea Oxford’s Conception 101 is coming to your rescue. 

Conception 101 

First things first, if everything is going to plan then you each bring a very important ingredient to the equation. Women contribute an egg and men contribute sperm.


The first key fact to understand is that women are born with all of their eggs. That’s right, women are born with around two million eggs and by the time they hit puberty around 300,000 remain and that decline continues. Once a month, every month from puberty to menopause, women ovulate, releasing eggs in the middle of their monthly cycle. The whole process is controlled by two glands in the brain - the hypothalamus and pituitary - which tell hormones in your body to trigger certain physical responses. The egg is released from a mature follicle on the ovary (either ovary - it’s random) and travels down the fallopian tube. Fertilisation may occur in the fallopian tube if sperm are present. 

The egg survives for about 12 – 24 hours. We go into greater detail about ovulation and your cycle in our Trying to Conceive section.


Men create sperm in the testes and they produce an average of 100 million sperm each and every day.  Over approximately three months, these sperm travel a system of tubes called the epididymis, maturing along the way before being released during ejaculation. Interestingly only around four per cent of sperm in an average ejaculation are considered normal & capable of fertilising an egg. After ejaculation, sperm are capable of fertilisation for about 72 hours. For some other cool sperm and male related facts, take a look at our Male fertility infographics.


After the sperm are deposited into the upper vagina via ejaculation, they must travel through the cervical mucus into the uterus and then into the fallopian tube before they can meet with the egg.


Female and Male Reproductive Systems 

Sperm make this long journey under their own steam (and with some help from upward contractions of the uterine walls). During the trip, sperm prepare themselves to meet the egg by subtle alterations of their heads (acrosome) and movement patterns. When they meet the outer membrane of the egg, the sperm start to burrow through it and then enter the egg itself. At the moment the first sperm successfully penetrates the egg, a reaction is triggered that makes the egg resistant to all other sperm. This single sperm absorbs into the egg, where the genetic material contained in its head fuses with that of the egg. Fertilisation is now complete.


After fertilisation, the combined egg and sperm - now known as an embryo - develops in the fallopian tube for the first three days, then travels down into the uterus. By the fifth day it will become a blastocyst, a hollow ball of cells surrounding a cyst-like cavity. Once the blastocyst breaks free from its shell, or hatches, it is ready to adhere to the surface of the endometrium.

You might be surprised to know that the average fertile couple in their 20s, having regular, unprotected sex, has just a 20 per cent chance of this happening naturally each month. You are at your most fertile around 22-23 years.

Top 10 - Tips to help increase fertility

Genea Oxford Medical Director Dr Richard Dover shares his Top 10 Baby Making tips, all designed to help you increase your chances of pregnancy:

  1. Don’t leave it too late! Women are born with all their eggs and they decline in both quantity and quality over time. As a result, the chance of a woman conceiving drops sharply in the mid-late 30s to early 40s.`
  2. Formulate a good diet and exercise routine. Women have a higher chance of conception when they are in a normal body mass index range and if either partner is overweight or obese, the chances of pregnancy are reduced considerably. In both men and women a BMI of 18.5-24.9 is considered normal. For further information please review
    • The importance of BMI for men 
    • The role of weight and BMI in women 
  3. Take appropriate preconception supplements. All women trying to conceive should take supplemental folic acid (folate) to ensure the best chance of a healthy pregnancy. Many women are also deficient in vitamin D and iodine.  
  4. Try to have sex about every other day, particularly leading up to the middle of your cycle.
  5. Know your cycle. Women with 28 day menstrual cycles usually ovulate midway between their menses – about 14 days after the start of their period. There are various simple methods of determining when you ovulate and that (and slightly earlier) is the best time to have unprotected sex.
    • Work out the best time to have sex with our ovulation calculator located on the right of this page
  6. Don’t smoke and significantly curtail alcohol and caffeine consumption. Smoking is toxic to human eggs and has long lasting negative effects even after a woman stops.
  7. Make sure your other half is also well and healthy, is not smoking and also reducing alcohol intake. It takes two to tango.
  8. Remember that your friends and even your mother – are not necessarily fertility experts despite their personal experiences. Their advice might be well meaning, but not necessarily accurate. 
  9. Try to relax! Obsessing about conception can be counterproductive and leave you so stressed that it affects your ovulation. Consider any strategies that reduce anxiety and help you remain positive.
  10. Live a normal and happy life. There is no evidence that you need to reduce normal levels of exercise or somehow wrap yourself in cotton wool while you are trying to conceive.