An expert in male fertility has called for urgent research into the stark decline reported in Western sperm counts (see BioNews 911).
Lifestyle factors, exposure to hormone-disrupting chemicals, disruption of fetal testes development, and trends in testicular cancer are four potential areas of research, said the expert in an editorial to the BMJ.
'Medical researchers cannot do it alone,' said Niels Skakkebaek, a professor of paediatric endrocrinology and andrology at the University of Copenhagen, and author of the editorial. 'We need health and research authorities that can see the urgent need for research in reproductive medicine, not just more infertility treatments, which are a short term solution for individuals not for the fertility of future generations.'
Earlier this year, a meta-analysis concluded that Western sperm counts had fallen by 52 percent between 1973 and 2011.
'Simple research questions urgently need answers,' the professor said.
He suggested the decline in sperm counts should be compared to trends in testicular cancer, as countries with a high incidence of this cancer also appear to report lower semen quality. Saying that rates in testicular cancer have more than doubled in recent decades, and increasingly in young men of reproductive age, this 'leaves little doubt that we should look into environmental causes – including lifestyle effects. Alterations in our genome cannot explain the observations as changes have occurred over just a couple of generations.'
Professor Skakkebaek also called for research into the impact of hormone-disrupting chemicals, such as pesticides, and maternal exposure could be linked to testicular dysgenesis syndrome, a male reproductive condition caused by disrupted testes development in the fetus. The professor first described this condition in 2001. Finally, he also questioned if decline in sperm could be correlated to lifestyle factors, including recreational drug use.
'Should we be worried about our future ability to reproduce ourselves, as some media coverage has claimed?' he asked.
'This inconvenient question makes sense when we look at what is going on in fertility clinics all over the world - more and more children are now born after in vitro fertilisation, intracytoplasmic sperm injection (ICSI), and insemination with partner or donor sperm.'
Professor Skakkebaek pointed out that despite the increase in live births from fertility treatment, fertility rates in many countries including Germany, Japan and Singapore remain well below the average of 2.1 children per woman. He also suggested use of ICSI may produce new generations with lower sperm counts (see BioNews 872).
Professor Allan Pacey of the University of Sheffield disagreed that increased use of assisted reproduction facilities or donor sperm were indicators of a male reproductive health problem, saying instead ‘this simply reflects changes in society brought about through economic development and social choice by couples about how many children to have and when to have them.'
However, he agreed that the increase in rates of testicular cancer as 'worthy of further investigation and is the most convincing argument I have heard for why we should be concerned.'
'These are indications of serious threats to male health in terms of infertility and male cancers. We must take notice and act to source the dangers and safeguard our mens' health,' said Sheena Lewis, emeritus professor of reproductive medicine at Queen’s University Belfast.