Sperm: all you need to know about producing ‘healthy swimmers’, and its other uses
- Eat and sleep well, drink and smoke less, keep them cool and ensure a regular turnover of stock – doctors’ tips for making the best sperm
- As well as making babies, they have uses in skincare and diet
Sperm is the cause of much boasting and jesting, but how much do we know about this life-bearing cell? Men brag about “healthy swimmers” – but what does that entail?
Sperm are produced and stored in the testicles and they have one main job, which is to impregnate a woman and pass on biological data to create a new human being. However, it would be a mistake to consider semen and sperm the same thing. Sperm make up just five to 10 per cent of an ejaculation.
This may seem a small proportion, but it equates to around 200 million sperm – and that many are needed because it is no mean feat for that one special sperm to reach and fertilise a woman’s egg. The egg and uterus do not help sperm navigate the minefield that is the vagina, and after that they must struggle against tiny hairs which line the Fallopian tubes, then fight through the thick layer that surrounds and protects the egg.
Experts believe this obstacle course offers the best chance of creating healthy offspring, since only the healthiest, strongest sperm will survive the journey. Many sperm aren’t up to the job. They are produced at such a rapid rate that Dr Andrew Yip Wai-chun, a Hong Kong-based urologist, says there are some with two heads and some with none and “all sort of alien looking”.
When it comes to sperm, size does not matter. A mature sperm cell is just 0.05 millimetres long, yet if all the sperm from one ejaculation were to line up, they would stretch over 10 kilometres.
Sperm cells have remarkable endurance, being able to survive inside a woman’s body for up to five days. Unlike a woman, who has a finite supply of eggs, a man is never in danger of running out of sperm and – if he so chooses – can continue making babies until the day he dies.
Nonetheless, human sperm pales in comparison to those of other creatures. While one man’s ejaculation produces around half a teaspoon of semen, the blue whale produces more than 400 gallons when it ejaculates (not surprising given its 2.4-metre-long penis).
African elephants release 200 billion sperm in each ejaculation. The humble fruit fly drosophila produces the largest sperm cells on the planet – they can reach a length exceeding 5cm, 20 times the length of the fly’s body.
Despite their resilience, sperm are simultaneously quite particular and need to be looked after. The scrotum regulates the temperature of the testicles and maintains it at 35 degrees Celsius, two degrees below the normal body temperature of 37 Celsius.
The temperature is kept low through veins that draw heat away and muscles in the scrotum that raise and lower the testicles to bring them closer or further from the body’s heat.
Wearing tight briefs and crossing one’s legs can increase the temperature of the testicles by two degrees. One 2018 study offered evidence to suggest that men who wore boxer shorts produced 17 per cent more sperm than those who wore briefs; however, the study’s authors said the results were not conclusive.
Could sperm be endangered? According to a 2017 analysis of nearly 43,000 men worldwide, sperm counts suffered a major decline between 1973 and 2011.
For optimal sperm production, as with most other aspects of health, it is crucial to eat well, consume less processed and junk food and more leans meat, whole foods, fruit and vegetables. Yip advises that “smoking, alcohol, use of illicit drugs, stress and fatigue, toxins and pesticides and most importantly heat in the scrotum” can all lower a man’s sperm count.
Doctors suggest men should ejaculate regularly for healthier sperm. Failure to achieve a climax reduces semen turnover, something which can trigger oxidative stress – a bodily imbalance that damages tissues and DNA, thus exposing the body to the risk of a variety of diseases. One study found that men who ejaculated four or more times a month had better sperm shape and structure.
For some people, sperm is used for more than making a baby – it’s a part of their diet. Paul “Fotie” Photenhauer, a San Francisco Bay area cookery book author, has published Natural Harvest – a collection of semen-based recipes.
The book’s blurb explains that, “Like fine wine and cheeses, the taste of semen is complex and dynamic. Semen is inexpensive to produce and is commonly available in many, if not most, homes and restaurants.”
Semen has been used as a skin cosmetic because it contains spermine, which is said to help clear acne and smooth wrinkles. Creams containing spermine sell for about US$200. During the first world war, semen was tested out as an invisible ink.
Sperm donation is on the rise. America and Denmark are big exporters of donor sperm.
Demand for sperm in China has surged since the one-child policy was abolished in 2016, but one sperm bank has quite specific requirements of its donors. The Third Hospital of Peking University will only accept sperm from those who “love the socialist motherland” and “support the leadership of the Communist Party”.