Why getting pregnant may be easier in summer

New research suggests that summer could be the most “fertile” season—and it’s not just because of all those pool swims. Scientists have found that sperm motility—the ability of sperm to move on its own—varies throughout the year, a factor that could influence advice for couples trying to conceive and the operations of sperm banks, reports The Post.

Researchers from universities in the UK, Canada, and Denmark analyzed sperm samples from over 15,000 men who donated at Cryos International clinics in Denmark and Florida between 2018 and 2024. They examined three key factors: ejaculate volume, sperm concentration, and motility.

The study found that while season had little effect on sperm volume or concentration, motility showed clear seasonal changes. In Northern Europe and the southern United States, the fastest sperm were most commonly observed in June and July, while motility was lowest in December and January.

“We were surprised by the similarity of the seasonal pattern across two very different climates,” said study co-author Allan Pacey. “Even in Florida, where temperatures remain high year-round, sperm motility still peaked in summer and dropped in winter. This suggests that environmental temperature alone does not explain these changes.”

Scientists speculate that factors such as daylight exposure, lifestyle, or other environmental conditions may play a larger role than previously thought.

Interestingly, these findings contradict some common beliefs about fertility. Many blogs and articles suggest that autumn and winter are the best times to conceive. CDC data from 2023 shows most babies were born in August, with the fewest in February—indicating conceptions occurred in late fall and early winter. Previous studies of menstrual cycles have also shown higher fertility in women during autumn and winter. Researchers note that differences in methodology and local climate could account for these discrepancies.

Nonetheless, the new data offers fresh insights into the male reproductive system. Pacey emphasizes that considering seasonal trends could become a useful tool for clinics working with couples trying to conceive. “These results expand our understanding of male health and may improve outcomes in fertility treatments,” he concludes.