MONTREAL — Human infertility is bound to grow around the world as more and more contaminants make their way into the environment, warns the co-chairman of an international conference on reproductive science being held in Montreal this week.
“Infertility is a serious problem,” said Bruce Murphy, a professor of reproductive biology in the faculty of veterinary medicine at the Université de Montréal.
“If you look at sperm counts of young men from 1950 until the present, you can see a decline over that period, and we believe it’s attributable — at least, in part — to environmental contaminants.”
A Canadian study last year found that in 1984, about five per cent of couples age 18 to 29 were infertile. By 2010, the infertility rate for that age group jumped to 13.7 per cent.
The obesity epidemic and the tendency of many women to get pregnant later in life are often cited as reasons for the rise in infertility. But a researcher at the University of Wisconsin-Milwaukee, Reinhold Hutz, is to present findings at the Montreal conference this week showing that “environmental contaminants have effects on the ovary and contribute to human infertility.”
Murphy noted that research in the 1960s found that pesticides like DDT interfered with the reproductive systems of eagles and peregrine falcons. Today, research has revealed that a compound used in many plastics, Bisphenol A (BPA), can interfere with the reproductive systems of lab mice.
“The BPA story was developed largely by (researchers) who discovered that when they got new plastic cages their mice stopped reproducing,” Murphy said.
Although may baby bottles are now sold as “BPA-free,” the compound is still found in the lining of food cans and even the paper on store receipts. Murphy predicted that other compounds — like brominated flame retardants that are used in some furniture — will likely be shown to disrupt the human reproductive system.
“We are now beginning to see the subtle effects of certain kinds of environmental toxins, and they are everywhere,” he added.
It’s not just human infertility that people should be worried about. Researchers are also grappling with rising infertility rates in dairy cattle.
Paradoxically, despite increasing human infertility, the global population is projected to climb from more than 7 billion today to 9.6 billion by 2050, according to a United Nations report.
“If the projections are right — particularly the projections about food supply which includes animal projects — we might not be able to keep up with the demand for food,” Murphy explained. “We’re going to have to produce more food for more people on less land. That’s one of the reasons why reproductive science is more important than ever.”
More than 1,200 scientists from around the world — including at least 80 from Quebec — will be attending the 46th annual meeting of the Society for the Study of Reproduction.
Other eagerly-anticipated studies that will be presented at the conference include one by Adam Watkins of the University of Nottingham in England showing that “maternal and paternal nutrition at the time of conception have an effect on the postnatal health of the offspring,” as well as the latest findings on embryonic stem cells.