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Related Experiment Video

Updated: May 10, 2026

Flow Cytometric Analysis of Biomarkers for Detecting Human Sperm Functional Defects

Flow Cytometric Analysis of Biomarkers for Detecting Human Sperm Functional Defects

Published on: April 21, 2022

Age thresholds for changes in semen parameters in men.

Bronte A Stone¹, Allyse Alex, Lawrence B Werlin

¹Reproductive Technology Laboratories, Los Angeles, California; Utah Fertility Partners, Pleasant Grove, Utah.

Fertility and Sterility

|July 2, 2013

Summary

Male fertility declines with age, with significant drops in sperm quality and count starting in the mid-30s. This age-related decline impacts pregnancy chances, independent of female age.

Keywords:

Aging and oligoasthenoteratozoospermia CASA human semen primary sex ratio sperm morphology

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Flow Cytometric Analysis of Biomarkers for Detecting Human Sperm Functional Defects

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Sperm Collection of Differential Quality Using Density Gradient Centrifugation

Sperm Collection of Differential Quality Using Density Gradient Centrifugation

Published on: November 29, 2018

Area of Science:

Reproductive biology
Andrology
Human reproduction

Background:

Male fertility is influenced by various factors, including age.
Understanding age-related changes in semen quality is crucial for reproductive health assessments.

Purpose of the Study:

To investigate age-specific thresholds for declines in semen quality parameters.
To determine the impact of male age on fertility outcomes.

Main Methods:

Retrospective analysis of 4,822 semen analyses and 259 fluorescence in situ hybridization (FISH) analyses.
Involved 5,081 men aged 16.5-72.3 years in a reference laboratory setting.

Main Results:

Semen parameters remained stable until age 34, with subsequent declines in total sperm number and motility.
Sperm concentration and morphology declined after 40, motility after 43, ejaculate volume after 45, and Y:X-bearing sperm ratio after 55.
These age-related changes are associated with oligoasthenoteratozoospermia.

Conclusions:

Male age >34 is associated with a reduced likelihood of pregnancy, increasing with advancing age.
Age-related declines in semen quality contribute to decreased fertility potential in men.
The study highlights the importance of considering male age in fertility evaluations.