Hi again signeti
Sorry to be awkward but there has been a lot of research done on this topic, the reason why there is a host of opinions is that there is no definitive answer, other than the effects must be relatively small.
Take a a look at
www.cdc.gov/niosh/topics/flightcrew for starters.
I know that this is an emotive issue but sadly you have to bear in mind that you have a roughly one in three chance of suffering from cancer at some time in your life and a roughly one in four chance of dying from it, wether you fly or not. As someone who lost both (non-flying) parents to cancer I'm more concerned about hereditary factors than radiation....and with that happy thought I'll bid you goodnight.
Rgds
Wiggy