Today in the journal Nature, reproductive biologists say they’ve reached a long sought-after goal in the field of male fertility. Japanese scientists were able to grow mature and fertile sperm in a test tube — and that sperm successfully joined with female egg cells and produced offspring.
Indeed, it’s been a exciting year for sperm. Big questions have been answered about possible causes of male infertility and future treatments, and we’ve unlocked some major mysteries about how sperm do their all-important job. Here’s a look at 5 of the most fascinating recent facts and findings on sperm and male fertility:
1. In the current study, scientists figured out how to take tissue from the male mouse testes and grow it into viable, fertile sperm outside the body in a culture dish. This might eventually help prepubescent boys undergoing cancer treatments to protect their fertility for the future.
2. Earlier this month, two separate findings in Nature explained exactly how sperm meets egg. When sperm sense the hormone progesterone (given off by cells around the egg) they become hyperactive, start beating their tails and swim towards their goal. When a man’s sperm lacks these progesterone sensors and a specific chemical channel, he is infertile.
3. Also this month, a study in the International Journal of Andrology gave us further evidence that fertility among men has been falling over the decades — a warning many scientists have been sending in recent years. The study looked at Finnish men born between 1979 and 1987 and found sperm quality to have fallen, citing possible environmental causes.
4. Recently, we found another reason to be concerned about bisphenol-A (BPA). Yet another study showed a link between BPA exposure and sub-par sperm. Whereas most of the earlier BPA-reproduction research has been in mice, this study looked at the correlation between the plastic chemical and sperm quality in human men. Pesticides have also been linked to falling sperm counts.
5. And finally, the most intriguing recent finding I’ve seen lately is that a dad’s diet and health habits may transfer through sperm — not in the passing down of genes, but in small tweaks to the sperm that result from dad’s lifestyle. In my view, we don’t fully appreciate just how important a father’s health and lifestyle are to the quality of his sperm and the future health of his offspring (we assume dad’s job is just to transfer genes).This study found that mice dads raised on high fat diets were more likely to have offspring with signs of diabetes.
Complicated little X and Y swimmers, no? It’s an exciting time in sperm and fertility research — I’m keeping a close eye on what’s next.