Men could be producing sperm that is too fast and powerful for successful fertilisation, a scientist has said, reports the Daily Mail.
In the UK, about one in six couples have trouble trying to conceive. Each year, nearly 35,000 women have IVF. Lifestyle, infection and pollution can’t completely explain the high levels of infertility, believes evolutionary biologist Dr Oren Hasson, from Tel Aviv University. He suggests super-sperm could be a factor.
Usually, when the first sperm reaches the egg, a woman’s body has a range of natural defences that will prevent all the other sperm reaching it. If more than that one sperm was allowed to reach the egg, a process called polyspermy would ruin the chance for successful conception.
Dr Hasson thinks these female barriers have evolved to force sperm to become more competitive. In response to this, men have started producing sperm that’s aggressive, fast and powerful. So fast and powerful the sperm have become, they beat a woman’s defence mechanisms, and ruin the process of fertilisation.
Men creating sperm that’s weaker because of stress or environmental factors then have even less chance of beating a woman’s improved defenses.