No, i a high gain antenna would not have any health effects to your family members. As i recall someone said to me once, you would get more harm from sitting in front of the tv, crt monitors, microwaves and (if you are really paranoid) cellphones.
I probably wouldn't stand right beside it. I would have it at least 6 ft away from anyone. Like redcyborg typed, its really not going to hurt anything. Its the directional antennas that you have worry about....
High gain antennas health problems? 
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