Getting offended is a bit silly, IMO, unless the person getting it wrong has ignored obvious signs. If you're going to be offended if someone mistakes your gender, make it obvious in your avatar/username/whatever!
Linford went for exactly this strategy, by choosing a well-known athlete's genitalia as his original username.

) the term IS referring to male bits, but was also used at one period to refer to priests, and this is where its usage to denote nonsense may have come from. So still maybe a little sexist, but an appropriate term for such a stew of nonsensical science.