The Patient's Guide to Embryology

One semen sample can contain hundreds of millions of sperm – each one genetically unique.

There are many ways sperm production can fail which is why male factor infertility affects around 35% couples who need IVF.

Unlike women, men continue to produce sperm for their whole lives.

Sperm production starts at puberty and continues for a man’s whole life thanks to regenerating stem cells in the testes. A single sperm cell takes approximately 74 days to make and grow to maturity. New waves of sperm production are starting every second meaning that there is a constant supply of sperm available – some men can produce 3000 sperm per second! You can’t run out by ejaculating too often but you also can’t save up sperm by avoiding ejaculation as mature sperm can only live for a few days in the testes before they die and are reabsorbed.

Sperm production can be disrupted more easily than you think

While a healthy sperm sample should contain at least 15 million sperm per ml, there are many factors other than sperm concentration which affect sperm function, their ability to fertilize and their ability to make healthy embryos. Sperm motility (how well they swim), sperm morphology (their appearance) and sperm DNA health are all key measures of quality and there are many ways that sperm production can go wrong. A man’s lifestyle has a big impact on testicular function and sperm are very vulnerable to damage both inside the testes and once they are ejaculated, something as simple as a hot bath, fever or too much cycling can drastically affect sperm production.

Take a closer look

Semen analysis results explained

A semen analysis is essential if you are investigating your fertility and the results make a big impact on your IVF treatment… Read more.

How to improve your sperm count

If your sperm count is low or your sperm are spinning around in circles, it may help to explain why they are finding it difficult to reach the egg for fertilisation… Read more.

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