What you need to know about sperm & semen

We have gathered some facts about semen and sperm and what is important to know in regards to male fertility and its reproductive abilities

The Difference Between Semen and Sperm

"Sperm" and "semen" do not refer to the same thing, but they are closely related. "Sperm" refers to the male reproductive cells themselves. "Semen" refers to the total fluid including sperm released during ejaculation. Semen consists of sperm cells and seminal fluid. The seminal fluid primarily consists of water and proteins, which give the fluid its viscosity. Additionally, enzymes, nutrients (such as fructose), and various minerals and antioxidants are also present.

Sperm production and maturation take place in the testicles through a process called spermatogenesis. Sperm cells, known internationally as spermatozoa, make up only a small portion of the total seminal fluid.

A man produces between 100 and 300 million sperm cells daily. The sperm are stored in the epididymis for approximately two weeks, after which they are either released through ejaculation or destroyed by the body. This ensures a continuous supply of sperm or reproduction. Sperm maturation takes a total of 72-74 days, and it's only in the last 10-14 days that the sperm cell is stored in the epididymis.

Sperm Motility

Sperm motility is the ability of sperm to move and swim effectively. It plays a vital role in a man's fertility potential since it directly impacts the ability of the sperm to reach and penetrate the egg for fertilization.

In a semen analysis, you measure the percentage of sperm that not only move but also swim in a coordinated forward manner. These are the sperm with the highest likelihood of successfully reaching the egg.

In technical terms, motility refers to the proportion of sperm that are in motion. Among these, the most noteworthy are those who can move and propel themselves forward. These are referred to as progressively motile sperm.

Sperm Count & Sperm Quality

The quality of the semen is determined by several parameters. Quantity is one parameter. Here, the primary focus is on the concentration of sperm in the sample, measured in millions per milliliter (million/ml). The total amount of sperm in the sample (concentration x volume) naturally also matters, as does the quality of the counted sperm.

A typical semen sample contains between 15 million and 200 million sperm per milliliter of semen. Even men with fertility issues can produce millions of sperm.

According to WHO's guidelines, a semen sample is considered normal if it contains a minimum of 1.5 ml of semen with at least 15 million sperm per ml, of which at least 40% are motile and at least 32% are progressively motile (moving forward). However, to become a sperm donor at Born, a donor needs to have much higher numbers than these. Therefore, a potential sperm donor will have to deliver a sperm sample.

At Born, we examine the sperm by determining the concentration of sperm and their mobility and movement pattern (motility).

What do sperm look like?

Some have two heads, some have two tails, some have a micro head, some have an excessively large head, and some have other abnormalities. In fact, normally only 4-8% of sperm are morphologically (=in terms of appearance) "correct" or "normal". Whether it's always a morphologically normal sperm that fertilizes the egg is difficult to determine for obvious reasons. However, morphologically normal sperm are considered the most suitable ones.

A significant number of irregularly shaped sperm are referred to as "abnormal" or having "abnormal morphology." The shape and structure of sperm are crucial for their ability to move effectively and fertilize the egg. When sperm have an abnormal or irregular shape, it can impact their ability to reach and penetrate the egg.

The head of the sperm is only 3x5 micrometers, and the tail is about 50 micrometers, which is smaller than a dust particle. This means that they are invisible to the naked eye. They have a unique structure, and the head of each sperm carries the genetic information (DNA), a midpiece that provides energy for movement, and a tail that helps them swim toward the egg during fertilization. Mature sperm swim at approximately 3 millimeters per minute.

If a large proportion of sperm have irregular shapes, it can have a negative impact on fertility and reduce the chances of successful fertilization. The irregular shapes can include sperm with tail or head anomalies or a combination of various abnormal traits.

How many sperm cells to fertilize an egg?

It takes only one sperm cell to fertilize the egg. When the sperm comes into contact with the egg, it attempts to penetrate its outer layer, also known as the zona pellucida.

After a sperm has penetrated the egg, the zona pellucida usually prevents other sperm from entering. This is called the zona blockade, ensuring that only one zygote is formed and preventing an abnormal number of chromosomes.

The zygote can split, thus giving rise to identical twins - but it's still only one sperm that has fertilized the egg. In the case of fraternal twins, two eggs have been released during ovulation and each has been fertilized by a different sperm.
How is sperm stored?

We employ cryopreservation to store sperm securely and efficiently. In this process, sperm is maintained in a frozen state within liquid nitrogen tanks, maintaining a temperature of -196 degrees Celsius. Cryopreservation ensures the genetic material remains unaffected and preserves the specimens' viability indefinitely.

At Born, we can provide you with a variety of storage options such as Donor Sperm Storage, Personal Sperm Storage and Known Donor Sperm Storage. You can read more about our storage options here.
Did you know that there are multiple things that can affect sperm quality?
- Sperm cells develop optimally at 35°C - two degrees below body temperature. When sperm is produced at higher temperatures, the genetic material becomes unstable as very high temperatures kill them.
- A general healthy lifestyle with a low-fat, nutritious, and varied diet, along with moderate exercise, often leads to better sperm quality. Conversely, a fatty diet, overweight, and high consumption of sugary drinks correlate with poorer sperm quality. However, not all studies are equally convincing, and it is still uncertain whether the link between the high consumption of sugary drinks and sperm quality is actually due to the sugary drinks or if the participants who consumed many sugary drinks simply lived more unhealthily than the other test subjects.
- Smoking can also reduce sperm quality.
- If one is stressed, it can affect their sperm quality.
- Even men with fertility problems can produce millions of sperm cells.
- That a high number of sperm cells doesn't necessarily guarantee male fertility, and a low number doesn't automatically mean there will be fertility problems.

"I hope that your future child will bring you joy and happiness."

Sperm processing for different fertility treatments - IUI or ICI

IUI sperm units can be used for all types of fertility treatments while ICI units are suited for vaginal inseminations, or in cases where your clinic prefers to process the sperm themselves.

GeneMatch is our ‘peace-of-mind’ service – we can test whether you and your donor share any genetic mutations that might increase the risk of your child inheriting a disease.

Keep reading for more detailed information.

IUI: IntraUterine Insemination

We process the donor sperm into IUI units which are then inseminated directly into the uterus at a fertility clinic. IUI treatments are recommended for women with no known fertility issues.

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ICI: IntraCervical Insemination

In ICI, donor sperm is placed high in the vagina, close to the cervix. This method is ideal for women with a healthy cycle who might prefer to be treated by their private gynaecologist rather than a clinic.

Learn more

GeneMatch

At Born we do everything we can to only accept donors with a healthy profile and no known issues. But your donor is only responsible for half of the future child's genes – the other half comes from you. GeneMatch screens for more than 400 genetic conditions to see if you and your donor are a good match.

Learn more