Cellphones give off electromagnetic waves that some researchers say effects certain biological functions.

Cleveland Clinic Foundation Director Ashok Agarwal and his research team found a correlation between the amount of time spent talking on a cellphone and a low sperm count, USA Today reported Monday.

Agarwal cautioned that the data are "quite preliminary" and the study didn't ask about other sources of electromagnetic waves or where the men kept their phones.

Other similar studies suggest that the proximity of the waves makes a big difference and Agarwal said he found sperm quality dropped in about an hour in lab tests where phones where left by semen samples.

Research teams, however, said the results of the lab tests don't definitively suggest that cellphones affect fertility outside of the laboratory.