Some time ago we noted reports by readers that certain email messages, when printed from Apple's Mail client, would be printed upside-down and/or backwards. MacFixIt reader Stephane Laroye notes a possible solution, posted in a thread on Apple's Discussions forums:
"When printing from Mail, the body of the message is printed backward (or mirrored) and upside down while the header prints correctly. The fix appears to be to increase the size of the message text (at least one increment) using Command- [or by using the "Bigger" toolbar item, if enabled, or by choosing Format -> Style -> Bigger]."
Stephane and other users in the above thread have reported the issue to Apple via the Mac OS X feedback page.