First of all; I have nearly 6 year old identical twin girls. I figure they are God getting even with my husband for every dirty thought he ever had about some other man's identical twin daughters. Someone already mentioned it, but you and your wife should read Dr. Barbara Luke's book, "When You're Expecting Twins, Triplets or Quads." Nutrition is so different for twins; you have to get all of your weight on quickly, they'll be early or there won't be room left for food. I had my twins at 34 weeks and they were 5'6oz. Good luck to you both!