Wine debate

So is it true that it is ok to drink a glass of red wine occasionally while pregnant? I was at a get together recently and was offered a glass of wine I turned it down because I wasn't sure if I should even though she told me her OB/GYN told her it was ok while pregnant. On the other hand a friend of mines says her OB/GYN told her absolutely no while pregnant. I haven't talked to OB/GYN yet but I wanted to know what all of you ladies where told.