Does male age affect fertility?
Yes — though the effect is gradual rather than a cliff, and it is less discussed than female age.
What declines
Semen parameters decline with age, and sperm DNA fragmentation increases. The AUA/ASRM guideline lists increasing paternal age among recognised contributors to sperm DNA damage, alongside environmental toxins, pollution, drugs, febrile illness and varicocele.
Testosterone also falls gradually with age, which can affect libido and erectile function.
What that means practically
There is no age at which men become infertile in the way women reach menopause. Men father children into later life routinely.
What changes is the probability per attempt, and the time it takes. Where both partners are older, the combined effect matters more than either alone.
The miscarriage and outcome question
Advanced paternal age is associated with miscarriage, and ASRM (2026) notes elevated sperm DNA fragmentation is associated with miscarriage. The size of that effect is modest compared with maternal age, which remains the dominant factor.
Associations have also been reported with some conditions in offspring. These are real but small in absolute terms, and worth understanding proportionately rather than as a reason for alarm.
What is worth doing
If you are an older man and your partner is having difficulty conceiving, get a semen analysis rather than assuming the issue lies elsewhere — and note that assessment of the male partner is frequently delayed.
Modifiable factors matter at any age: stopping smoking, moderating alcohol, healthy weight, treating chronic conditions, reducing heat exposure, and avoiding testosterone and anabolic steroids.
Sperm DNA fragmentation testing is not recommended in initial evaluation. It is indicated where there is recurrent pregnancy loss, or unexplained infertility with concurrent difficulty.
The honest framing
Male age matters, and it is under-discussed relative to female age. But it is not a reason to panic if you are in your forties, and it does not change the basics — get tested, address what is modifiable, and allow three months for changes to show.
Sources
- AUA/ASRM — Diagnosis and treatment of infertility in men (2021)
Frequently Asked Questions
At what age does male fertility decline?▾
Male fertility begins declining gradually from the mid-30s and more noticeably after 45. The most important change is rising sperm DNA fragmentation — from ~15% at age 25 to ~30–40% by age 50. Time to pregnancy increases significantly after 45. Sperm count and production continue throughout life, but quality declines measurably.
Does paternal age affect IVF success?▾
Modest effect, more apparent after age 50. Most studies find little impact up to age 45. After 50: slightly lower blastocyst development rates and higher miscarriage rates. ICSI partially mitigates motility effects but not DNA fragmentation. PGT-A embryo testing reduces miscarriage risk in couples with older male partners.
Is it safe to have a baby with an older father?▾
Most children of older fathers are healthy. The absolute risk of conditions associated with advanced paternal age (autism, schizophrenia, achondroplasia) remains low. Population studies show associations with paternal age over 50. Genetic counselling is reasonable for couples where the male partner is over 50 or there is a history of miscarriage.