Skip to main content

Health condition · Clinically reviewed

Male infertility, explained - from semen analysis to ICSI.

Male factors play a part in roughly half of all couple infertility. Most causes are identifiable, and many are treatable - a structured work-up beats guesswork.

Jump to treatment
A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE CG156, BAUS and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK andrology pathways including semen analysis standards, ICSI and surgical sperm retrieval.

Key facts

Male infertility at a glance.

The essentials, in plain English - what it is, why it happens, and how it’s investigated and treated in the UK today.

  • What it is

    A male factor contributing to roughly half of all couple infertility cases - either as the sole cause or alongside a female factor.

  • Main categories

    Pre-testicular (hormonal), testicular (production), post-testicular (obstructive) and ejaculatory disorders - each needs a different work-up.

  • Most common cause

    Varicocele is the most frequently identified and correctable testicular cause of reduced sperm quality.

  • Key investigation

    Semen analysis against WHO reference values, usually repeated twice, underpins the whole assessment.

  • Idiopathic cases

    A significant proportion of men have no clearly identified cause despite full investigation.

  • Treatment range

    From lifestyle change and hormone therapy through to ICSI and surgical sperm retrieval, depending on the cause.

Why this guide matters

A structured work-up, not months of uncertainty.

Male infertility is common, under-discussed, and usually explainable once properly investigated. The three points below shape everything else on this page.

  • It’s a couple’s issue, not a blame game

    Male factors contribute to around half of couple infertility cases - investigating both partners together avoids months of delay.

  • Semen analysis drives every decision

    Concentration, motility and morphology against WHO reference values decide which pathway - lifestyle, surgery or assisted reproduction - is right.

  • Even severe cases have options

    From gonadotrophins for hormonal causes to micro-TESE and ICSI for azoospermia, modern andrology offers a route forward in most cases.

How the diagnosis is made

From twelve months of trying to a clear cause.

The steps a UK GP, andrologist or urologist will normally follow, per NICE CG156 - so you know what to expect and why.

  1. 01

    Assessing

    Twelve months trying

    Referral for investigation typically follows 12 months of unprotected intercourse without conception - see our infertility guide.

  2. 02

    Assessing

    Semen analysis

    Two samples assessed for concentration, motility and morphology against WHO reference criteria.

  3. 03

    Assessing

    Hormone profile

    FSH, LH and testosterone distinguish hormonal (pre-testicular) causes from primary testicular failure.

  4. 04

    Confirming

    Physical examination

    Testicular volume, presence of a varicocele, and whether the vas deferens can be felt on each side.

  5. 05

    Confirming

    Scrotal or transrectal ultrasound

    Identifies structural causes - varicocele, obstruction, or absence of the vas deferens.

  6. 06

    Confirming

    Post-ejaculatory urinalysis

    Checks for sperm in the urine when retrograde ejaculation is suspected, often linked to diabetes or prior surgery.

  7. 07

    Specialist

    Genetic testing

    Karyotype, Y-chromosome microdeletion and CFTR testing for severe oligozoospermia or azoospermia - specialist commissioned genetics.

  8. 08

    Specialist

    MDT specialist review

    Andrology, urology and fertility medicine work together, alongside Fertility Network UK for support.

Typical timeline: initial semen analysis results within one to two weeks; full work-up within a few months.

Symptoms

What male infertility actually looks like.

Often there’s nothing to notice at all beyond the couple not conceiving. When there are clues, they point towards a specific underlying cause.

  • No obvious symptoms

    Most men have no other symptoms - the couple simply hasn’t conceived after 12 months of trying.

  • Low libido or gynaecomastia

    Can point towards hypogonadotropic hypogonadism or hyperprolactinaemia as an underlying cause.

  • Small or asymmetric testes

    Reduced testicular volume or asymmetry may reflect cryptorchidism, Klinefelter syndrome or prior torsion.

  • A visible or palpable varicocele

    A “bag of worms” feeling above the testicle - the most common correctable testicular cause.

  • History of mumps or chemotherapy

    Mumps orchitis, chemotherapy and radiotherapy can all impair sperm production, sometimes permanently.

  • Cloudy or absent ejaculate

    May suggest retrograde ejaculation, particularly in men with diabetes or after pelvic surgery.

  • Difficulty with erections or ejaculation

    Erectile dysfunction or premature ejaculation can itself limit natural conception - see our erectile dysfunction guide.

  • Red flag - absent vas deferens

    A vas deferens that cannot be felt on examination raises suspicion of CBAVD and a CFTR gene link to cystic fibrosis.

Treatment

How male infertility is treated in the UK.

Lifestyle change first, targeted correction of the underlying cause next - and assisted reproduction or surgical sperm retrieval where needed.

  • Lifestyle optimisation

    Stopping smoking, reducing alcohol, weight loss, avoiding heat exposure and steroids - first-line for every man, whatever the cause.

  • Hormonal therapy

    Gonadotrophin treatment can restore fertility in hypogonadotropic hypogonadism and Kallmann syndrome - specialist endocrine or andrology led.

  • Varicocele repair

    Selective surgical or radiological correction for men with a clinically significant varicocele and abnormal semen parameters.

  • Surgical correction of obstruction

    Reconstructive surgery for infection-related scarring or ejaculatory duct obstruction where anatomy allows.

  • IUI, IVF and ICSI

    Assisted reproduction escalates from intrauterine insemination through IVF to ICSI, which is particularly effective for severe male factor infertility.

  • Surgical sperm retrieval

    TESE, micro-TESE or PESA retrieve sperm directly from the testis or epididymis for obstructive or non-obstructive azoospermia - specialist commissioned.

  • Donor sperm

    An option when no viable sperm can be retrieved, discussed openly with the couple and with counselling support.

  • Fertility preservation

    Sperm banking before chemotherapy, radiotherapy or other gonadotoxic treatment protects future fertility options.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, urologist or fertility specialist knows your history and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Fertility problems: assessment and treatment (CG156).

  • British Association of Urological Surgeons (BAUS). Male infertility guidance.

  • World Health Organization. WHO laboratory manual for the examination and processing of human semen.

  • European Association of Urology (EAU). Guidelines on sexual and reproductive health.

Red flags

When it needs urgent attention.

Most male infertility work-up is unhurried and outpatient. These situations aren’t - and need a faster response.

  • Testicular lump or hard swelling

    Any new firm testicular lump needs urgent same-day assessment to exclude testicular cancer, not just infertility work-up.

  • Sudden severe testicular pain

    Could indicate testicular torsion - a surgical emergency requiring immediate attention, not a routine fertility appointment.

  • Absent vas deferens (CBAVD)

    Strongly associated with CFTR mutations - warrants genetic counselling and CF carrier testing for both partners before assisted conception.

  • Klinefelter syndrome features

    Small firm testes, gynaecomastia and tall stature in a man with azoospermia should prompt karyotype testing.

  • Severe oligozoospermia or azoospermia

    Very low or absent sperm counts need genetic testing (karyotype, Y-microdeletion, CFTR) before proceeding to assisted reproduction.

  • Before gonadotoxic treatment

    Sperm banking should be discussed and arranged before chemotherapy or radiotherapy starts, ideally within days, not weeks.

  • Signs of hypogonadism

    Reduced libido, erectile difficulty, fatigue and low muscle mass alongside infertility warrant a full hormone work-up.

  • Psychological impact

    Infertility carries a significant emotional burden for men - low mood or relationship strain deserves proactive support, not silence.

Living with it

A treatable condition, approached as a couple.

Four things that make the biggest difference while you’re going through investigation and treatment together.

A quiet reminder

A diagnosis is a starting point, not a verdict.

Even severe male factor infertility has a route forward for most couples through modern andrology and assisted reproduction.

  1. 01 Lifestyle

    Small changes add up

    Stopping smoking, moderating alcohol, losing excess weight and avoiding hot tubs or tight cycling shorts can measurably improve semen parameters over three months.

  2. 02 Timing

    Sperm takes about 72 days to mature

    Any change - lifestyle or medical - takes roughly three months to show up in a semen analysis. Recheck results after that window, not sooner.

  3. 03 Together

    This is a couple’s journey

    Male factor infertility is never just one partner’s issue to solve alone - shared appointments and shared decisions ease the process considerably.

  4. 04 Support

    Ask for psychological support early

    Fertility Network UK and specialist counselling can help with the stress of investigations, delays and difficult decisions along the way.

Frequently asked

Everything we get asked about male infertility.

Quick answers on causes, semen analysis, varicocele repair and ICSI.

  • What causes male infertility?

    Causes fall into four broad groups - pre-testicular hormonal problems, testicular causes such as varicocele or genetic conditions, post-testicular obstruction such as CBAVD or a prior vasectomy, and ejaculatory disorders like retrograde ejaculation. Lifestyle and environmental factors can worsen any of these. A significant number of cases remain idiopathic despite thorough investigation.

  • How is male infertility diagnosed?

    The core investigation is semen analysis, usually done twice, checked against WHO reference values for concentration, motility and morphology. This is combined with a hormone profile, a physical examination looking for a varicocele or absent vas deferens, and scrotal ultrasound where a structural cause is suspected.

  • Is varicocele repair worth doing?

    Varicocele is the most common correctable testicular cause of reduced sperm quality, but repair is selective - it’s usually offered when the varicocele is clinically significant and semen parameters are abnormal, rather than to every man with a varicocele found incidentally.

  • What is ICSI and when is it used?

    Intracytoplasmic sperm injection involves injecting a single sperm directly into an egg during IVF. It is particularly effective for severe male factor infertility, including very low sperm counts or sperm retrieved surgically from the testis.

  • Can sperm be retrieved surgically if none is in the ejaculate?

    Yes - for azoospermia, procedures such as TESE, micro-TESE or PESA can retrieve sperm directly from the testis or epididymis, whether the cause is obstructive or non-obstructive. This is specialist commissioned care done alongside fertility services.

  • Does lifestyle really affect sperm quality?

    Yes. Smoking, excess alcohol, obesity, anabolic steroid use and repeated heat exposure to the testes are all linked to reduced sperm concentration and motility. Because sperm takes around 72 days to mature, improvements from lifestyle change typically take about three months to appear on a repeat semen analysis.

Related content

Keep reading.

Pulse Healthcare concierge

Send us your enquiry

A concierge service for UK private healthcare. We match you with the best vetted clinics and consultants in our network - they then contact you directly.

So we can match you to the right clinician close to you.

We reply to every enquiry within 24 hours (Mon–Fri). Confidential - your details are never shared outside our vetted consultant network.