When a couple has trouble conceiving, the focus still tends to fall on the woman first. Yet according to the NHS, around one in seven couples in the UK has difficulty getting pregnant, and male factors are involved in a large share of those cases. For many men, fertility simply isn't something they think about until it becomes a worry.
The good news is that men's fertility is often easier to assess, and in many cases easier to influence, than people expect. Two things are central to it: how much sperm you produce, and the hormones that drive that production, with testosterone the best known.
How sperm production works
Sperm are made continuously in the testes, and the full process from start to finish takes around two to three months. That timeline matters: the sperm you produce today reflect your health over the past few months, not just the past few days.
Production depends on a chain of hormonal signals. The brain releases hormones that tell the testes to make both testosterone and sperm. The testes also need to stay slightly cooler than the rest of the body, which is why they sit outside it. Anything that disrupts these signals or raises the temperature can affect sperm output.
The link between testosterone and fertility
Testosterone plays a key role inside the testes, where high local levels are needed for healthy sperm production. When overall testosterone is low, men may notice symptoms such as reduced sex drive, fatigue, low mood, erection problems or a loss of muscle strength.
But the relationship isn't as simple as "more testosterone means more sperm". In fact, one of the most important things for men trying to conceive to know is this: taking testosterone from outside the body, whether as replacement therapy, gels or anabolic steroids, can sharply reduce sperm production, sometimes to zero. The body detects the extra hormone and switches off its own signals to the testes.
That's why anyone trying for a baby should speak to a GP before starting any testosterone treatment or supplement aimed at boosting hormone levels.
Signs worth paying attention to
Many men with low sperm count have no symptoms at all. Still, some signs are worth mentioning to a GP:
- Low sex drive or difficulty getting or keeping an erection
- Persistent tiredness or low mood without an obvious cause
- Pain, swelling or a lump in the testicles
- A history of undescended testicles, testicular surgery, mumps after puberty or cancer treatment
- Reduced facial or body hair, or breast tissue growth
Lifestyle changes that make a difference
Because sperm take a few months to develop, changes you make now can show up in your results by the time the next batch is ready. The factors with the strongest evidence include:
- Stopping smoking, which is linked to lower sperm count and quality.
- Keeping alcohol within recommended limits, as heavy drinking can lower testosterone and sperm production.
- Reaching a healthy weight, since excess body fat can disrupt hormone balance.
- Avoiding overheating, such as long hot baths, saunas and laptops resting on your lap.
- Steering clear of anabolic steroids and testosterone products unless prescribed.
- Sleeping well and managing stress, both of which affect hormone levels.
Testing: where to start
You don't have to wait until you've been trying for a year to get a first impression. A home sperm test gives a quick indication of whether your count is above or below 15 million per millilitre, the lower reference level set by the World Health Organization. Tests like this don't measure how well sperm swim or their shape, so they're a screening step rather than a full assessment.
If you also have symptoms that could point to low hormone levels, a testosterone test can add useful context. Testosterone is usually highest in the morning, so tests are often best taken early in the day. Whatever the result, discuss it with your GP rather than acting on it alone.
A low or borderline result isn't a diagnosis, and it doesn't mean conception is impossible. It's a reason to take the next step, which is usually a full semen analysis arranged through your GP.
When to see a GP
The NHS advises seeing a GP if you've been trying to conceive for a year without success, or after six months if your partner is 36 or older. Go sooner if you have any of the signs listed above or a known history that could affect fertility. Both partners should be assessed, as problems on either side are common.
Key takeaway
Men's fertility deserves the same attention as women's. Sperm count and hormones are closely linked, but simple assumptions, such as boosting testosterone to improve fertility, can backfire. Understanding the basics, making a few lifestyle changes and checking early can help you and your partner make informed decisions.
