Bio 101: How Sperm are Made

The machinery that makes sperm is a marvel of biology. This article explores the micro world of sperm production and the key factors that affect proper sperm development.

How sperm are made

Every second, the average man produces 1,500 sperm adding up to over 500 billion over the course of his life. The machinery that makes sperm is a marvel of biology with a single goal in mind – creating life. This article explores the micro world of sperm production and the key factors that affect proper sperm development.

Meet the Sperm

A wonder in its own right, the sperm cells is the single densest cell in the male body. It is lean and mean with all systems focused on optimizing its ability to swim to and fertilize the egg. The sperm cell is only in 0.05mm long (about 2 thousandths of an inch) but has to swim over 152 mm (around 6 inches) from the base of the woman’s cervix to the fallopian tube where it will fertilize the egg. If scaled to human size, this is a distance of almost 3 1/2 miles. The fastest sperm cells can cover this distance in 30-60 minutes, overcoming daunting obstacles along the way. To accomplish this feat, the sperm cell is engineered to be one of natures’ great wonders.

Spermatogenesis: Sperm Production Step-by-Step

Start to finish, it takes 72 days or 2 ½ months to make a sperm. During that time, the it will travel through over 25 ft of microtubes in the testicle. Each sperm starts as a germ cell which divides and undergoes meiosis to become a baby sperm, or spermatid. The spermatid is nourished by nurse cells in the testicle and it slowly grows a tail. After it is fully developed, it is released from the nurse cells and sent into a long tube, called the epididymis, where it learns to swim and is stored until it is ejaculated out of the body.

Sperm production (spermatogenesis) starts in the brain where the hypothalamus constantly monitors blood testosterone levels as an indicator of testicular activity. As blood testosterone levels droop, the hypothalamus fires up and begins secreting GnRH (gonadotropin-releasing hormone) which flows directly to the pituitary gland causing it to produce luteinizing hormone (LH) and follicle stimulating hormone (FSH).

Luteinizing hormone travels from the pituitary gland to the testicle where it stimulates leydig cells to secrete testosterone. FSH then concentrates that testosterone into the seminiferous tubule where sperm are made. Germ cells lining the inner walls of the tubules undergo a special process called meiosis that splits the parent cell DNA in half and rearranges it into new, unique combinations. Each one of these new cells will become a sperm cell.

Sertoli cells absorb testosterone that has been concentrated in the seminiferous tubule. Then, much as a mother nurses a young child, they provide testosterone and key micronutrients to baby sperm cells (spermatid). As they develop, the spermatids are pushed towards the center (lumen) of the seminiferous tubule to make room for new cells that are created at the edge. Upon reaching the center of the tubule, the adolescent spermatids grow tails and are released to be carried out of the testicle and into the epididymis. In the epididymis they finish maturing, learn to swim and are stored until they are ejaculated out of the body. Sperm can live in the epididymis for about three weeks. If not ejaculated within that time, they will die and be reabsorbed by the body.

Sperm DNA: How your genes are passed on

Sperm cells are sophisticated packages for delivering DNA to the egg to create a new genetically unique person. As awesome of a specimen as you are, Mother Nature does not simply pass along an exact duplicate of your genes on to your offspring. Instead, your DNA is rearranged into millions of unique combinations, so that each sperm cell carries a slight (and hopefully improved) variation of you.

To understand how, you need to take a closer look at your own DNA. You have 46 chromosomes that contain all your genes. Each chromosome is paired, so there are 23 sets or pairs of chromosomes. One set of 23 chromosomes are given to you by your father and the other set by your mother. Each cell in your body contain all 23 pairs.

In the normal life of the cell, the DNA is unwound in a long chain of spaghetti so that the cell can use it to create proteins that enable the body to function properly. You can think of genes as instructions to the cells for how to build proteins. Slight alterations in genes cause slight alterations to the proteins they create. For example, there are several genes that instruct the cells in your scalp to create proteins that become the hair on your head. Alterations to those genes will alter color, texture and shape of your hair. They can also cause disposition to baldness. Each of your cells contains two copies of every gene, one from your mom and one from your dad. When the genes are different from each other the cell has two options. It can follow the instructions given by a dominant gene or it can blend the instructions given by the both genes much as a cook improvises using two recipes to make a new dish.

When sperm cells are created, DNA is taken through two steps. First the two pairs of chromosomes are brought together, chopped up and reassembled causing some of the chromosomes to have a mixed set of genes coming from both parents. Then, the pairs are divided so that one of the chromosomes goes into one sperm cell and the other goes into a second sperm. The resulting sperm will end up with some genes that are entirely from your mother, some from your father, and some that are a blend of the two. The last chromosome is known as the sex chromosome and contains an X from your mom and a Y from your dad. When the pairs split during the formation of sperm, the X goes into one sperm and the Y goes into another. The means that half of the sperm are female and half are male.

Optimal Environment for Sperm Maturation

Fine-crafted machines need precise environments to ensure proper function. Sperm are incredibly sensitive to alterations in temperature. For proper development, they require an average temperature of approximately 93.5 degrees Fahrenheit. The scrotum is cleverly engineered for temperature control. The outermost layer is thin, stretchy skin specially designed to allow for movement and air cooling. The next layer in is a thin muscular sac called the cremaster muscle that contains and supports the testicle like a hammock. As it relaxes allowing the testicle to hang lower, the cremaster thins out allowing air to cool things off. If the scrotum gets too cold or when the testicle is threatened, the cremaster contracts drawing the delicate organ in towards the body and forms a thicker, more protective layer around it.

Read more about heat and male infertility.

Decontamination Systems

As motile cells, sperm generate a significant amount of metabolic bi-product known as reactive oxygen species (ROS). Similar to exhaust that comes out of a car, ROS is the bi-product from the sperm’s engine burning sugars and nutrients to generate energy. Small amounts of ROS help sperm in the process of fertilization, but large amounts of ROS can injure and even kill sperm cells. The body’s natural defense against reactive oxygen species is the release of antioxidants. Antioxidants, such as vitamin C and vitamin E, are typically molecules that contain double-bonded carbon that enables them to easily bond to and neutralize reactive oxygen species.

Micronutrients & Sperm Production

There are a number of key nutrients that are important for proper DNA replication and sperm cell development. Here are some of the top nutrients that support proper sperm development

Coenzyme Q10: Converts food into an energy source for cells & serves as an antioxidant
Folic Acid: Provides critical molecules needed for DNA replication
Selenium: Helps to regulate hormones, serves as an antioxidant & supports the structural integrity of the sperm neck-piece that connects the head to the tail.
Vitamin E: Fat soluble antioxidant
Vitamin C: Supports the development of key amino acids necessary for cell division & serves as a powerful antioxidant.
Zinc: A building block for testosterone, semen, sperm and the prostate. Perhaps the manliest nutrient on earth

Learn more about nutrients that support sperm health.

Sara SDx

Sara SDx

Editor of Don't Cook your Balls, Co-Founder of, Health Coach and Men's Health Advocate. Passionate about sperm, men's health and helping people build their families.
Sara SDx

Author: Sara SDx

Editor of Don't Cook your Balls, Co-Founder of, Health Coach and Men's Health Advocate. Passionate about sperm, men's health and helping people build their families.

37 thoughts on “Bio 101: How Sperm are Made”

  1. i am doing more and more masturbation and i am trying to leave but i am unable to leave masturbation please suggest me what i have to do my body is going un healty day by day pleas3 tell me what masturbation effect on mind .Is it damage the power of thinking ? please reply sir/mam

    gmail –

    1. Masturbation can become an addiction. The best advice is to spend your time outside — doing things that engage your mind in new ways. Exercising, working, visiting new places, making friends. This can help you have a more balanced mind and reduce your need to masturbate.

  2. hi, i understand the roughly 90 day sperm cycle, my question is regarding alcohol.
    I understand alcohol can damage or kill sperm.

    If someone binge drinks on 1 night out, but normally is a light drinker.

    Does that one night binge kill the sperm that would be ejaculated the next day or 2 or 3 days?
    Does that one night out binge kill the sperm that would be ejaculated in roughly 90 days? and the sperm that would be ejaculated the day after the drinking binge would be ok.

    1. It hasn’t been studied well enough to know all that well. My guess is that there would be a minor drop over the course of the 3 months but not enough to really notice.

      Depending on how high blood alcohol got, some of it could directly hurt sperm that are currently developed / developing which might show up as reduced motility, morpphology or count. It also impacts the liver’s ability to break down nutrients that are critical in cellular division which would hurt new sperm that are currently being produced.

      The impact would be light as it was only a few hours of exposure. So overall I wouldn’t worry too much.

      If you had a habit of binge drinking the effects would compound and can have a dramatic impact on sperm. If you keep it to 1x per every 3 months or so, I think it’s reasonably safe.

      Let me know if that makes sense to you.

  3. Hi
    Could u pls tell wether my husband’s semen report is normal. We are trying to conceive a baby but we are not getting any positive result

    Colour is whitish
    Ph reaction is 7.2
    Liquidation time is > 1 hr
    Total sperm count 95.8 million/ml
    Morphology normal form is 85% and abnormal form is 15%
    Pus cells 4-6
    And coming to MOTILITY, we couldn’t find the result properly they just mentioned the grades like
    Grade 4 – 40%
    Grade 3 -20%
    Grade 2. – 20%
    Grade 1. – 10%
    Grade 0. – 10%
    This is why we are unable to judge the result properly, pls suggest us. Thank u

    1. How long have you been trying? How often are you able to meet?

      This report looks pretty good. Sperm count is high, motility is good (the higher the grade the better and most of your sperm are in the top grades), morphology is great.

  4. My husband and I are trying to conceive. He doesn’t have super low counts for his sperm, but 24 million isn’t all that great either. He has about 1/2 of the testosterone they would consider normal. We have never had issues getting pregnant before (we have three kids), but we’ve been trying now for 7 months. I am perfectly healthy in the baby-growing department. Hubby has been trying to boost his count. He picked up this Pregnenolone. He thinks it could help. Testosterone treatment killed his sperm count, which is why he’s down to 24 million (from 60 million in August). We are trying to get it back up. Will the Pregnenolone help or hurt his count? Information is scant.

  5. If you don’t ejaculate frequently enough, the body doesn’t just absorb the dead sperm cells. It can cause problems where you get little globules like little balls of jelly that are firm and can actually cause some discomfort when you do eventually ejaculate. If you have waited long enough, it can take 5-10 ejaculations before you are able to clear all that stuff out. I was freaked out when it happened to me. I was injured and on medication for a couple weeks and didn’t even really think about it but I guess it killed my sex drive and eventually when I was off the medication and back to normal, there was that issue. Super weird. But normal apparently. I’ve looked it up on several sites and threads. People even say they have gotten women pregnant while that was happening to them. But I want to be clear, this is not “blue balls” and I personally don’t think “blue balls” even exists. The discomfort I mentioned comes from actually ejaculating what are basically like little rice grain sized squishy jelly beans (if you will).

  6. When x and x are meet than baby sex is female when x and y are meet than male.but in which case the baby sex is neither male nor female.i mean ‘chhaka’

  7. I was found sperm count of 6ml. can it be raised by the diet to a normal level? or by pills only?

Comments are closed.