It’s a biological reality that casts a shadow over the aspirations of many child-free women under 30: between the ages of 35 and 40, fertility takes a sharp decline.

At 30, the odds of getting pregnant per cycle hover around one in five. By the time 40 rolls around, this chance drops to just one in 20. This stark reality often pushes women to start families earlier than they might prefer, sometimes at the expense of their careers.

Popstar Lily Allen recently highlighted this dilemma, candidly remarking that her children, born when she was 26 and 27, significantly impacted her career trajectory.

“It really irks me when people suggest you can have it all because, frankly speaking, you can’t,” the singer asserted in an interview with UK publication Radio Times.

However, experts increasingly stress that concerns about the biological clock aren’t exclusive to women. Professor Geeta Nargund, a fellow in the Royal College of Obstetricians and Gynecologists and founder of Create Fertility, emphasized this point, stating, “For too long, there has been a prevailing misconception that fertility and the biological clock are solely women’s issues.”

Nargund pointed out that the risk of miscarriage doubles for women whose partners are over 45 compared to those with partners under 25. Research indicates that sperm quality and count begin to decline after the age of 25 in men, as revealed in a comprehensive 2015 analysis of 90 studies encompassing over 90,000 participants.

Despite discussions on increasing infertility rates and delayed maternal age in the US, attention often neglects the rising age of first-time fathers. Census data confirms a significant increase in both male and female infertility over the last three decades, partly attributed to women delaying childbirth. In 1990, the median age for mothers at birth was 27; by 2019, it had risen to 30.

Experts stress that the rising age of first-time fathers is a critical issue that warrants more attention.

Dr. Lisa Webber, an OBGYN with over 20 years of experience, highlighted the impact of older fathers, stating, “We shouldn’t solely blame women.” A 2021 study from Belgrano University in Argentina found a higher rate of miscarriages among couples with male partners aged 40 or older.

While fertility complications with age are well-documented for women due to declining egg quantity, men experience a slower decline in fertility. Dr. Scott Lundy, a urologist at the Cleveland Clinic, explained, “As we age, the testicles, like any other organ, don’t function as well as they used to.” Various factors contribute to this decline, including decreased libido, erectile dysfunction, and molecular changes affecting sperm shape, concentration, and mobility.

Moreover, older sperm is prone to more DNA mutations, increasing the risk of birth defects and miscarriages. Experts attribute these mutations to replication errors in the germ line, exacerbated by age. Lifestyle factors such as smoking, STIs, and malnutrition can also impact sperm quality over time.

Accepting this reality may be uncomfortable, but it’s crucial for men to acknowledge. Nargund emphasized the importance of educating men about fertility health and its natural decline with age, as ignorance may hinder conception efforts in the future.

Sperm, all you need to know