Thank you for bringing up an interesting subject!
A coworker of mine has several adopted children who have Fetal Alcohol Effect and Fetal Alcohol Syndrome. She, understandably, has very strong feelings about avoiding alcohol during pregnancy, and I sure don't begrudge her that, but I was frankly shocked to hear some of the pseudoscience she uses to support her opinions. She stated unequivocally that "when you drink, the systems that build the baby, that decide which cells will be brain cells and which will be skin cells, are themselves drunk, so everything goes in all wrong. It doesn't matter how much alcohol you've consumed--*any* amount will cause that." When another colleague mentioned the attitudes and behaviors of mothers in other countries, she first chalked their lower FAS rates up to lower rates of binge drinking compared to the U.S. (and I thought, okay, that's sensible), but then added, "mostly, though, it's because Europeans have built up a different tolerance over generations of alcohol use, so you don't see it as much over there." Um... that's not how tolerance... works?
Anyhow, the last thing I want to do is throw this particular coworker under the bus--I really do understand how she would be 100% opposed to any usage of alcohol at all. But it's hard not to hear these arguments and think, "So, this is the best mainstream American medicine has got for us?"
I personally have a sip every now and then, and after the first trimester will have a beer on the occasional evening. And am frankly pretty rabid on the subject of what expecting mothers are and aren't "allowed" to do, in general.