Sperm are produced in the testicles during a process called spermatogenesis. A self-renewing population of stem cells called spermatogonia continually give rise to sperm precursor cells that are carefully nurtured and protected during their transformation into fully developed sperm. Sperm then find their way into the epididymis, an organ on the back of each testicle where they gain the ability to swim and are stored until their call to action.
Making sperm requires a complex and delicate array of biological processes. DNA needs to be accurately copied, efficiently packaged, and equally sorted. Proteins must be manufactured and assembled into functional machines to power each sperm. Critical crosstalk between sperm and cells in the epididymis facilitates important functions like swimming ability (motility).
Making sperm is delicate work. DNA needs to be copied, edited, and packaged. Proteins must be manufactured and assembled. Round typical appearing cells need to be nurtured and transformed into hydrodynamic, high energy swimmers. All of these processes are sensitive to the environment in your body, which is heavily influenced by your habits and behavioral choices.
So how long does it take to see a fertility impact of a lifestyle or behavioral choice? Are your swimmers doomed forever from a past night (or many) of too much partying? When can you know that sperm present in an ejaculated sample weren’t produced during a prior ongoing bad habit?
The best research to answer this question came out of the University of California system in 2006. Using an elegant radio-isotype research design, researchers showed that it takes more than two months for newly produced sperm to start to become detectable in ejaculated semen samples. By three months, at least 70% of the sperm population in a man’s semen is composed of newly produced sperm. Interestingly, though, this group’s data did show that some old sperm can hang around for at least 3 months.
How do we interpret this data? It tells us that a change in habits or behavior starts to impact the health and quality of your ejaculated sperm about two months after the change. The major impact begins to become apparent at the three month time point, when most of a man’s ejaculated sperm are new sperm produced after the change. Lingering older sperm from the past are often present, however, even three months later. It probably takes 4-6 months to see the full impact of habit and lifestyle modifications on male reproductive health. What are you waiting for?
