Pressure
Sorry guys. Has got nothing to do with avgas, radar enviroments, its actually pressure changes.
Closest was Capt Snooze.
Read an article few years back, saying that people involved in regular pressure changes, i.e, scuba divers and pilots are more LIKELY to have female siblings. Though of course this does not always occur.
As for scuba divers more LIKELY having male siblings I don't know, but I could be wrong.
Though it does all have to do with pressure.
SU/C