When I’m in spaces of mostly those of childbearing age, be that a professional or personal space, it’s hard to avoid the topic of our biological clock. A biological clock determines a person's ability to get pregnant as they get older, with the general consensus suggesting that it becomes more difficult with age. 

And, generally, biological clocks are mostly associated with being considered to be a thing only people with uteruses need to consider. Fortunately, it turns out these statistics are not as dire as they initially sound. But there’s more to conception than just the age of the egg bearer.

Yes, we’re talking about people with penises now. 

Why are men left out of the biological clock conversation?

The emphasis on the biological clock has been placed on people with uteruses because they are born with a set number of eggs that they slowly shed throughout their lives during their menstrual and ovulation cycles. Egg quantity decreases over time, but research suggests egg quality could decrease over time, too. 

People with penises, on the other hand, make new sperm every day. Because of this continuous sperm supply chain, it’s been assumed that men should be able to reproduce at any age. Now, researchers and doctors are starting to look at the relationship between aging and sperm, and learning that the biological clock may be something for everyone to consider. 

Men’s hormones change over time

As men age, changes occur in their bodies. For example, there is a decline in the hormones necessary to regulate sexual function:

• Testosterone and Estrogen: Both are required for sperm production. With age, levels of testosterone and estrogen decrease. 
• Dehydroepiandrosterone (DHA): DHA contributes to many male sexual characteristics that define puberty. DHEA helps produce other hormones, most notably, testosterone and estrogen. DHA also decreases with age. 
• Follicle-stimulating hormone (FSH): FSH stimulates testicular growth and aids in the production of healthy sperm. High FSH may mean the testicles are not working properly. Age among other factors can affect FSH levels . 
• Luteinizing Hormone (LH): LH is responsible for testosterone production, which is in turn responsible for sperm production. LH can increase with age, which can also impede the production of testosterone, and therefore, the production of sperm.

Let’s talk about sperm quality 

Have you heard people say, “wow this used to be so much easier when I was younger,” while talking about playing a sport or doing any other physical activity? It’s the same with sperm production. While this may seem obvious, as men age so do their sperm. While they may create new sperm every day, as men age it becomes harder to do things with the same level of quality. Sperm can lose their quality — or “fitness” — throughout someone’s lifetime, just like any other part of the body.

Do men have a biological clock cut off?

Another reason why the biological clock conversation is so prevalent for those with uteruses, is due to menopause. Twelve months after a person's last menstrual cycle, that person is considered to have gone through menopause. This means they are no longer producing eggs and can no longer become pregnant. People with penises do not have such a specific biological cut-off and continue to produce sperm throughout their lives. In theory, people with penises could reproduce at any age, but due to the reasons detailed above, this is not completely accurate. Just because they are producing sperm at an old age, it doesn’t necessarily mean they will be fertile. 

More people are waiting until they are older to reproduce, for a myriad of societal and biological reasons. It’s important to continue to stay healthy and check in with your partner and your doctor if you are hoping to conceive. By being communicative about your wants, medical needs, and your desire for reproduction, a proper plan can be developed.