A 50 per cent drop in sperm count sounds like a lot but what the research published in Human Reproduction Update in July really shows is that 47 million sperm per mililitre is the new normal. Men are still fertile but probably have fewer high quality sperm than their Dad did 25 years ago. The earlier generation were more likely to have 99 million sperm wriggling in each mililitre of semen. Despite the drop, it’s important to remember that reproduction only needs one sperm to reach the egg and that people are still having babies.

Technique matters

I’ve been skeptical in the past that the drop in sperm count is anything other than a result of our improved ability to count sperm. Studies that compare data gathered over time rarely take into account the significant changes in lab techniques made across the years that enable us to actually count and study sperm. This paper did pique my interest though because it only included data from studies that used the best sperm count technique we have.

Don’t wait

My own published research has found that lifestyle factors don’t really have a significant impact on sperm quality. This means that waiting to start fertility treatment until after you’ve exercised more or cut down on your drinking won’t make a difference as there is little evidence that changes like this boost semen quality. There are actually very few identifiable lifestyle factors that can explain poor sperm quality in adult men. If you are worried that your sperm count may be too low to help achieve a healthy pregnancy the best advice I can give is to start trying for a baby sooner rather than later.

We need evidence

We now have evidence that sperm counts are in greater decline in the post industrial countries of North America, Europe and Oceania than in Asia, South America or Africa. What we don’t have is evidence that explains this global difference. It’s too easy to say it’s because of lifestyle or exposure to man-made chemicals, I think these conclusions are premature. 

Plan ahead

What we know right now is that sperm counts have dropped, what we don’t know is exactly why. What evidence of the 50 per cent drop in sperm count among men in the West does do is give us a new benchmark. The data is the best we currently have available, so this is a step forward. If we start well-thought-out studies now, though, we could make a leap.

Future answers

Men are still becoming fathers and healthy babies are still arriving but it would be in everyone’s best interests to track sperm counts now and in the future. If we plan better studies then it’s possible that in another 25 years we might be able to understand why sperm quality is in decline. The debate is yet to be resolved, that’s why we need excellent research to tell us what could be driving such extreme changes in semen quality.