There is no new evidence to suggest that we now need an outright ban - I had an occasional glass of wine when I was pregnant and have two healthy strapping boys - I recall speaking to my GP about what was allowed and what wasn't and his answer was that with the exception of heavy drinking and smoking (or drugs), there is little chance of things like eating the occasional underdone egg or bit of pate etc. would harm your baby but that worrying about it would spoil your enjoyment of your pregnancy. He said quite rightly that the best reason to avoid these things was that if there was anything wrong with your baby, you would tend to blame yourself when actually there is little chance that you did anything. My advice would be to do what feels right for you. FAS is caused by regular drinking, if you have had the odd glass then I wouldn't be too concerned, but if it makes you feel better to stop then do.
I believe that statistics show that the majority of babies are unplanned and I would imagine that lots of these were conceived after drinking - and most people seem to turn out ok.