1. Headline
  1. Headline
By Robert Bazell Chief science and health correspondent
NBC News
updated 7/20/2011 2:35:46 PM ET 2011-07-20T18:35:46

A newly discovered cause of infertility could allow millions of infertile couples around the world to have a child. Researchers have found a common gene mutation that causes sperm to be far less able to swim through the mucus of the cervix and reach the egg.

  1. More from TODAY.com
    1. Mila Kunis,  Ashton Kutcher welcome baby girl

      Mila Kunis and Ashton Kutcher welcomed a baby girl Tuesday night, People magazine reported. No name was announced.

    2. 9 things we learned from Brian Williams' Facebook chat
    3. Plaza producer: TODAY's #PinkPower event was 'my best day on the job'
    4. Guess who's most likely to hand out candy, and which kind they've got
    5. Lunch box hero: You've got to see this dad's amazing napkin art

Normally, the gene causes the production of a protein called beta-Defensin 126 or DEFB126, which coats the surface of sperm. When the gene is mutated, the protein is missing, and the sperm have that problem in transit, according to researchers at the University of California, Davis, in a report published Wednesday. Wives of men with the genetic variation were less likely to become pregnant than other couples and 30 percent less likely to give birth, the researchers said.

About 15 percent of couples are infertile — a condition defined by the World Health Organization as the inability to achieve a pregnancy after a year of trying. In just under one third of the cases, the problem is with the man. Underdeveloped or abnormal sperm can cause male infertility, as well as hormone imbalances or certain medications. But many cases of unexplained infertility are likely connected to this genetic variation, the researchers suggested.

One reason this discovery is important is that the normal tests of the quality of sperm, such as examining them under a microscope and watching how quickly they move, do not detect the mutation. But with this new information a simple genetic test should soon allow doctors to find it easily. For couples who have the genetic mutation doctors can use insemination to get the sperm right next to the eggs and overcome the handicap. If that relatively simple intervention doesn't work, they can resort in vitro fertilization, even injecting a single sperm into the egg, if necessary.

It appears that about one in every 250 men has this genetic mutation.

The work was carried out by doctors and scientists from UC Davis; Simon Fraser University in Burnaby, BC, Canada; the  University of Leicester I, UK; Anhui Medical University in Hefei, China; and the University of Illinois, Chicago. It was published in the journal Science Translational Medicine.

© 2013 NBCNews.com  Reprints

Discuss:

Discussion comments

,

Most active discussions

  1. votes comments
  2. votes comments
  3. votes comments
  4. votes comments

More on TODAY.com

  1. Joan Lunden: 10 things I wish I knew before I was diagnosed with breast cancer

    From the moment you hear the words ‘You have breast cancer,’ it’s almost like you’re shot out of a cannon. Here are 10 things I wish I knew before I was diagnosed.

    10/1/2014 10:52:45 AM +00:00 2014-10-01T10:52:45
  2. Want to help? A guide to breast cancer charities

    In the United States an estimated 296,000 women and 2,240 men will be diagnosed with breast cancer this year and almost 40,000 women and 410 men will die of the disease. That's one death every 14 minutes, according to the National Breast Cancer Coalition.

    10/1/2014 10:45:11 AM +00:00 2014-10-01T10:45:11
  3. Samantha Okazaki / TODAY
  1. Nbc News

    9 things we learned from Brian Williams' Facebook chat

    10/2/2014 1:41:28 AM +00:00 2014-10-02T01:41:28
  1. Noel Vasquez / Getty Images Contributor

    Mila Kunis,  Ashton Kutcher welcome baby girl

    10/2/2014 1:24:09 AM +00:00 2014-10-02T01:24:09
  1. Kevin Lamarque / Reuters

    Secret Service director resigns amid scandal

    10/1/2014 7:30:52 PM +00:00 2014-10-01T19:30:52
  1. Texas Ebola patient had contact with kids

    Texas Gov. Rick Perry said in a press conference on Wednesday that “some school-age children” had been identified as having contact with the man diagnosed with the first case of Ebola in the United States. 

    10/1/2014 5:37:52 PM +00:00 2014-10-01T17:37:52