There's a new study out on mobile phone use and it's not good news for men.
Israeli scientists have found there's a link between where we keep our phones and our fertility levels.
Few of us are found without our phones, but could phones in pant pockets be bad for would-be dads? A new study says maybe.
Israeli scientists tested 106 men who attended a fertility clinic.
Among those who kept a phone near to their groin, nearly half had lowered sperm levels -- more than four times higher than those who didn't. They also found that talking on a phone doubled the chances of low sperm quality.
If it was also charging, the risk doubled again.
Mobile phones are small radio transmitters, which mean that they're too small to damage our DNA but can warm up the tissue they pass through.
The Israeli scientists speculate it's this heat and electromagnetic activity that damages the testes' ability to make sperm.
NZ fertility experts say the study's too small to be definitive but that doesn't mean people should totally disregard it.
"This could impact fertility, slightly," says Dr Dean Morbeck, Fertility Associates scientific director. "It's not like knocking fertility out, but it's enough that if you are trying to have a child and you are going through fertility treatment it makes sense that you might want to alter behaviour so that you can minimise chances of this if it indeed exists."
So those wanting to start a family might want to keep their phone away from the family jewels.