If you’re anything like me, when you heard that both Al Pacino and Robert DeNiro became fathers again at the ripe old age of 83 and 79, respectively, you might have been like, “Are you kidding me?” after you picked your jaw off the floor.

While it’s no surprise that older men can father children — heck, Abraham in the Bible was 100 years old when he sired Isaac — it does raise the question: Does sperm count ever decrease?

After all, women are constantly told, if not frightened, with stats and figures about the fragility of our fertility. We understand that by age 30, our ability to get pregnant starts to decline and only continues to decline faster once we reach 35. Then, by the time we turn 45, getting pregnant naturally is unlikely.

So, what about the men? Do they ever stop being baby makers? Is sperm even healthy past a certain point?

When it comes to answering what seems to be an important question, Zuri Fertility’s Co-Chief Medical Officer, Dr. Omer Raheem, admits the research isn’t there.

“Recent studies have said that men’s sperm may lose their fertility capacity, sperm count, and function over time for men over 40,” he tells Scary Mommy. “However, more research is currently underway to further validate and confirm these findings.”

When asked if sperm count decreases with age, Raheem says recent studies “point to this, but more research needs to be done to validate it.”

One study found that semen quantity peaked between the ages of 30 and 35 and was found to be lowest after age 55.

Another Stanford University School of Medicine study found that babies born to fathers of an “advanced paternal age,” meaning those older than 35, had increased risks at birth, such as low birth weight, seizures, and need for ventilation immediately after birth. According to the data, men 45 or older were 14 percent more likely to have a child born prematurely, and men 50 or older were 28 percent more likely to have a child that required admission to the neonatal intensive care unit.

While more research needs to be done, here’s what we do know about the quality and health of a man’s fertility as he ages.

Why are men still fertile well into their senior years?

What makes Pacino and DeNiro such stallions? Raheem says male fertility could be seen as a window into men’s health and wellness. “As older men maintain a healthy lifestyle, regularly exercise, and eat a balanced diet, sperm qualities may remain active with significant fertilization potentials leading to successful pregnancy with their partners,” he says.

What factors affect a man’s sperm as he ages?

According to Raheem, several factors could impact men’s fertility and sperm qualities, such as advanced age, environment and gonadotoxic exposures, smoking, chronic medical conditions, and genital injuries. “Age is not the sole contributing factor in determining men’s ability to fertilize an egg and achieve pregnancy,” he explains.

For lifestyle and environmental recommendations that improve male fertility, Raheem suggests excessive heat avoidance, regular exercise, a healthy diet, and removing marijuana and tobacco smoking. He also recommends restricting exposure to “wet heat” from hot tubs, saunas, steam baths, and whirlpools, which can decrease sperm production for up to three months.

Taking supplements like Theralogix, Fertiaid, vitamin C, folic acid, zinc, and pumpkin seeds can also improve fertility.

What are the risks of fathering a child at any age?

Although advanced age in men could contribute to unhealthy pregnancy, Raheem says much of the research in this area “has been in the form of epidemiological studies that lack specific couple clinical and pregnancy outcomes and an inability to confidently correlate the advanced paternal age to unhealthy pregnancy. Moreover, pre-implantation genetic testing can offer much-needed information about the conception well-being and development.”

However, he does share that getting older has been shown to have an inverse association with total sperm motility, progressive motility, normal sperm morphology, and sperm concentration.

There are numerous other risk factors when fathering a child at any age.

“Obesity, for example, is associated with reduced sperm morphology and sperm concentration,” Raheem explains. “Environmental factors such as exposure to pollutants including methyl mercury, pesticides, organic solvents, radiation, endocrine disrupting compounds, and even mobile phones have also been found to compromise male reproductive function.”

Other factors include smoking, drinking alcohol, and even cell phone usage. “Additionally, there is increasing evidence of an association between male infertility and systemic disease, including malignancies, autoimmune conditions, and high-risk behavior,” he says.

“There is also evidence of worsened overall health with worse semen parameters. If these trends are accurate, this overall suggests the need for an increased focus on a thorough history and physical evaluation in infertile men, and that if certain parameters are worsening, perhaps this is reflective of additional previously undiagnosed medical disease, especially in young men who may otherwise not seek medical care.”

When it comes to conceiving, Raheem says that men who wish to be fathers should focus on improving their health and well-being, which may, in turn, improve overall health and fertility.