The Virginia Commonwealth University School of Medicine may be responsible for one of the biggest medical breakthroughs of the 21st century. According to researchers, a genetic factor may predict an inability to conceive in men.

At the heart of the research findings was the meiosis expressed gene 1, or MEIG1. This protein is responsible for the final stage of spermiogensis, or formation of sperm in the testicles. During this final stage, the DNA is added to the sperm and the head and tail are formed. In mice that lacked this protein, the resulting sperm were not formed correctly and thus, were unable to fertilize the female egg.

The male mice also had lower levels of Parkin co-regulated gene, PACRG protein which works with the MEIG1 during sperm production. The researchers believe that the MEIG1 levels are just as important as the relationship between MEIG1 and PACRG.

In addition to finding a potential genetic cause for infertility, doctors involved in the study also believe the proteins could lead to form of male contraception similar to those used by women today. The male contraceptive could lower MEIG1 levels to the point where the sperm produced are infertile. When the male wishes to reproduce, the contraceptive could be stopped and, theoretically, the MEIG1 levels would return to normal.

Source: Proceedings of the National Academy of Sciences - September 2009