How Male Fertility Works: What Every Man (and Partner) Should Know

In conversations about fertility, the focus often leans heavily toward female biology—but male fertility plays an equally critical role in conception. And yet, most men don’t learn the basic science of how their own reproductive system works unless they’re facing challenges with conception firsthand.

Understanding the fundamentals of male fertility isn’t just for those trying to start a family—it’s important knowledge for anyone who wants to be proactive about their health. So here’s a simple, science-backed primer on what every man (and his partner) should know about how male fertility works.

The Journey Begins: Sperm Production 101

Sperm are made in the testes through a process called spermatogenesis, which takes about 64 days. This process is continuous—healthy men are producing millions of new sperm daily.

Inside the testes, seminiferous tubules act like sperm factories. These tiny, coiled tubes are where immature sperm cells develop and mature before moving into the epididymis, where they gain the ability to swim and fertilize an egg.

The Hormonal Command Center

Male fertility is regulated by a finely tuned hormonal system called the hypothalamic- pituitary-gonadal (HPG) axis.

Here’s how it works:

• The hypothalamus in the brain releases GnRH (gonadotropin-releasing hormone).

• This signals the pituitary gland to release two key hormones:

Without healthy levels of these hormones—and without the right sensitivity of the testes to respond—sperm production can be compromised, even if testosterone levels seem "normal."

Sperm Motility & Function

Producing sperm is only part of the story. For conception to occur, sperm must be:

• Motile: capable of swimming effectively toward the egg.

• Morphologically normal: shaped correctly to penetrate the egg.

• Numerous: a high enough count to increase chances of fertilization.

Sperm health can be influenced by a range of factors, including age, lifestyle, environmental exposures, medications, and underlying medical conditions. Unlike women, who are born with all their eggs, men continually produce sperm throughout their lives—so the potential for change (and improvement) is there.

Fertilization: The Male Role in Conception

At ejaculation, sperm mix with fluid from the prostate and seminal vesicles to form semen. During intercourse or assisted reproduction, sperm must navigate a hostile environment in the female reproductive tract to reach and fertilize the egg. It’s a biological marathon where only the fittest sperm will reach the finish line.

Why This Matters

Fertility is often seen as a “female issue,” but up to 50% of infertility cases involve male factors. Despite this, many men delay evaluation or are unaware that common things—like heat exposure, smoking, poor sleep, certain supplements, or even excessive cycling—can impact sperm health.

Whether you’re planning a family now or in the future, understanding how male fertility works empowers you to take control of your reproductive health—and opens up conversations that are too often stigmatized or overlooked.

Let’s normalize talking about male fertility. 

The science is clear: reproductive health is a shared responsibility. And it starts with knowledge.