Alright, guys, stay with me on this one ...

If you father one child, you raise your risk of developing prostate cancer over men who don't have any kids. Paradoxically, if you father more than one child, you reduce your risk of developing the disease. And, if your child turns out to be a girl, your risk of prostate cancer again rises somewhat. These somewhat convoluted findings come from a study published in the January 2007 issue of the peer-reviewed journal Cancer.

A study of 3,400 men helped Danish researchers arrive at these findings. While they were not able to find any environmental factors that may be causing this risk fluctuation, more investigation into the child number/gender theory still needs to be done before it can be considered conclusive.