Men who are racking up the minutes on their cell phones may be paying for it with decreased fertility, a new study shows.

The study out of Cleveland finds that men who talk for more than four hours a day on their cell phone have a lower sperm count.

The research team at the Cleveland Clinic Foundation studied 361 men under the age of 40 who were being evaluated for infertility.  They broke the men up into groups based on their daily cell phone usage.  Those who talked more than four hours a day had lower counts, more poor "swimmers" and abnormally formed sperm.

The study's author, Ashok Agarwal, says one reason could be heat generated by the phones because sperm production is sensitive to temperature.  He also found that sperm left sitting next to a cell phone in talk more for an hour showed a decrease in quality.

Don't panic yet, men.  Agarwal says the results are very preliminary and were conducted in a lab environment, not in the real world.

The study can be found in the journal Fertility and Sterility.