Scientists are getting closer to understanding the causes of male infertility. According to a study published in the journal Reproductive Biomedicine Online, damage to the DNA in #sperm occurred among 40 percent of study participants, who were couples receiving in-vitro fertility treatments. Research also has found that sperm damage is responsible for an estimated 80 percent of previously unexplained cases of male infertility. But there are steps #men can take to reduce that sperm damage, such as quitting smoking. "It's good news," says one of the researchers, fertility expert Sheena Lewis, a professor of reproductive medicine at the Centre for Public Health at the Queen's University in Belfast, Northern Ireland. "Eighty percent of men who previously were unexplained, we've now got a cause. Once you find a diagnosis, you can do something." Sperm is a tightly wrapped packet of DNA with a tail attached and a single goal: Get to the egg and fertilize it to make a baby. "Being able to swim and having good DNA are the only things that matter," says Dr. Lewis.
Usually, when men's sperm is tested during fertility work-ups, doctors check for how healthy the sperm look under a microscope, how many there are in a given space, and how well they move. These are important factors, but Lewis says that this data doesn't correlate all that well with live births. Because of that, she and her colleagues have spent the better part of a decade looking for more in-depth information about sperm that could help predict the success of conception and live births.
Instead of results that tell you what portion of your total sperm count isn't behaving well enough for fertility, Lewis and her colleagues developed the SpermComet assay, a test that unravels the DNA packet inside sperm and reveals the amount of damage in each one. All men have some level of damage in some sperm, and most of the time, it is not enough to affect fertility. The cutoff point, after which the sperm are too damaged for fertility, is about 25 percent damaged, she says. Not only do these damaged sperm reduce the odds of conception, but they also increase the chances of miscarriage if conception does occur.