@hawkeye10,
My apologies.
Please note that I am not laying a direct clausal connection between A) the drinking and B) the mental/physical defects of the infant.
I didn't do that because it wasn't relevant to my point.
The thing that matters is if, when you land in that situation, and you (inevitably, if you are a concerned and involved parent) think about what you might have done wrong, things like the drinking will swim to the surface.
But even if it's not been a factor, and even if it was in fact entirely beneficial, how are you going to convince the people around you of this fact? All they have seen, all they probably will remember, is seeing you with an alcoholic beverage in your glass. They can't know whether you limited yourself or not, and will probably always wonder.
Also, there's one more thing to consider:
A rather large percentage of people have a hard time distinguishing the line between 'just a few drinks' and 'drinking too much'. Should they be tempting themselves by drinking at all during a pregnancy?